Internet Engineering Task Force (IETF) C. Petrucci
Request for Comments: 6109 DigitPA
Category: Informational F. Gennai
ISSN: 2070-1721 A. Shahin
ISTI-CNR
A. Vinciarelli
April 2011
La Posta Elettronica Certificata - Italian Certified Electronic Mail
Abstract
Since 1997, the Italian laws have recognized electronic delivery
systems as legally usable. In 2005, after two years of technical
tests, the characteristics of an official electronic delivery
service, named certified electronic mail (in Italian "Posta
Elettronica Certificata") were defined, giving the system legal
standing.
The design of the entire system was carried out by the National
Center for Informatics in the Public Administration of Italy
(DigitPA), followed by efforts for the implementation and testing of
the service. The DigitPA has given the Italian National Research
Council (CNR), and in particular the Institute of Information Science
and Technologies at the CNR (ISTI), the task of running tests on
providers of the service to guarantee the correct implementation and
interoperability. This document describes the certified email system
adopted in Italy. It represents the system as it is at the moment of
writing, following the technical regulations that were written based
upon the Italian Law DPR. November 2, 2005.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It has been approved for publication by the Internet
Engineering Steering Group (IESG). Not all documents approved by the
IESG are a candidate for any level of Internet Standard; see Section
2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6109.
Petrucci, et al. Informational [Page 1]RFC 6109 Certified Electronic Mail April 2011
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Petrucci, et al. Informational [Page 2]
RFC 6109 Certified Electronic Mail April 2011
Table of Contents
1. Introduction ....................................................5
1.1. Scope ......................................................5
1.2. Notational Conventions .....................................6
1.2.1. Requirement Conventions .............................6
1.2.2. Acronyms ............................................6
1.2.3. Terminology and Definitions .........................7
2. PEC Model .......................................................8
2.1. System-Generated Messages ..................................8
2.1.1. Message Types ......................................10
2.2. Basic Structure ...........................................12
2.2.1. Access Point .......................................12
2.2.2. Incoming Point .....................................14
2.2.3. Delivery Point .....................................16
2.2.4. Storage ............................................17
2.2.5. Provider Service Mailbox ...........................17
2.2.6. Provider Service Email Address .....................17
2.3. Log .......................................................17
3. Message Processing .............................................18
3.1. Access Point ..............................................18
3.1.1. Formal Checks on Messages ..........................18
3.1.2. Non-Acceptance PEC Notification Due to
Formal Exceptions ..................................19
3.1.3. Non-Acceptance PEC Notification Due to
Virus Detection ....................................20
3.1.4. Server-User Acceptance PEC Notification ............20
3.1.5. PEC Transport Envelope .............................21
3.1.6. Timeout Delivery Error PEC Notification ............23
3.2. Incoming Point ............................................24
3.2.1. Server-Server Acceptance PEC Notification ..........24
3.2.2. PEC Anomaly Envelope ...............................25
3.2.3. Virus Detection PEC Notification ...................27
3.2.4. Virus-Induced Delivery Error PEC notification ......28
3.3. Delivery Point ............................................29
3.3.1. Checks on Incoming Messages ........................29
3.3.2. Delivery PEC Notification ..........................29
3.3.3. Non-Delivery PEC Notification ......................34
3.4. Sender and Receiver Belonging to the Same Domain ..........34
3.5. Example: Complete Transaction between Two PEC Domains .....34
4. Formats ........................................................35
4.1. Temporal Reference ........................................35
4.2. User Date/Time ............................................36
4.3. Format of a PEC Message Body ..............................36
4.3.1. User Readable Text .................................37
4.3.2. Original Message ...................................37
4.3.3. Certification Data .................................37
4.4. Certification Data Scheme .................................37
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4.5. PEC Providers Directory Scheme ............................39
4.5.1. providerCertificateHash Attribute ..................41
4.5.2. providerCertificate Attribute ......................41
4.5.3. providerName Attribute .............................41
4.5.4. mailReceipt Attribute ..............................42
4.5.5. managedDomains Attribute ...........................42
4.5.6. LDIFLocationURL Attribute ..........................43
4.5.7. providerUnit Attribute .............................43
4.5.8. LDIFLocationURLObject Object Class .................44
4.5.9. Provider Object Class ..............................44
4.5.10. LDIF File Example .................................44
5. Security-Related Aspects .......................................48
5.1. Digital Signature .........................................48
5.2. Authentication ............................................48
5.3. Secure Interaction ........................................49
5.4. Virus .....................................................49
5.5. S/MIME Certificate ........................................49
5.5.1. Provider-Related Information (Subject) .............50
5.5.2. Certificate Extensions .............................50
5.5.3. Example ............................................51
5.6. PEC Providers Directory ...................................55
6. PEC System Client Technical and Functional Prerequisites .......55
7. Security Considerations ........................................55
8. IANA Considerations ............................................56
8.1. Registration of PEC Message Header Fields .................56
8.1.1. Header Field: X-Riferimento-Message-ID: ............56
8.1.2. Header Field: X-Ricevuta: ..........................56
8.1.3. Header Field: X-VerificaSicurezza: .................57
8.1.4. Header Field: X-Trasporto: .........................57
8.1.5. Header Field: X-TipoRicevuta: ......................57
8.1.6. Header Field: X-Mittente: ..........................58
8.2. Registration of LDAP Object Identifier Descriptors ........58
8.2.1. Registration of Object Classes and
Attribute Types ....................................58
9. References .....................................................59
9.1. Normative References ......................................59
9.2. Informative References ....................................61
10. Acknowledgments ...............................................62
Appendix A. Italian Fields and Values in English ..................63
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1. Introduction
Since 1997, the Italian laws have recognized electronic delivery
systems as legally usable. In 2005, after two years of technical
tests, the characteristics of an official electronic delivery
service, named certified electronic mail (in Italian Posta
Elettronica Certificata, from now on "PEC") were defined, giving the
system legal standing.
This document represents the English version of the Italian
specifications
(http://www.digitpa.gov.it/sites/default/files/normativa/
Pec_regole_tecniche_DM_2-nov-2005.pdf); the Italian version is the
normative PEC reference.
IETF review did not result in community consensus. Since this
specification describes existing deployment and implementation, the
issues identified by the IETF community have not been addressed in
this document. However, these issues would need to be addressed
before a successor to this document could be published. At a
minimum, the successor document would need to include:
* A clear statement of the requirements/goals that need to be
satisfied by the protocol;
* A comprehensive diagram and description of the overall message flow
and delivery sequence required to achieve the requirements;
* Alignment with traditional terminology for IETF email and security
* A review of prior art; and
* A replacement of the unregistered LDAP DN name space used in this
specification, which may lead to conflict with other registered or
unregistered names, with a registered name space.
1.1. Scope
To ensure secure transactions over the Internet, cryptography can be
associated with electronic messages in order to provide some
guarantee on sender identity, message integrity, confidentiality, and
non-repudiation of origin. Many end-to-end techniques exist to
accomplish such goals, and some offer a high level of security. The
downside of end-to-end cryptography is the need for an extensive
penetration of technology in society, because it is essential for
every user to have asymmetric keys and certificates signed by a
Certification Authority. Along with that, users would need to have
an adequate amount of knowledge regarding the use of such technology.
Petrucci, et al. Informational [Page 5]RFC 6109 Certified Electronic Mail April 2011
PEC, on the other hand, uses applications running on servers to
digitally sign messages, thus avoiding the complexity end-to-end
systems bring about. By doing so, the user need only have an
ordinary mail client with which to interact. The downside is that
the level of security drops, since the protection does not cover the
entire transaction. Nonetheless, application is simpler and does not
require specific user skills, making it easily more widespread among
users.
This document describes PEC's technical aspects and features. It
presents the details of the protocol and the messages that are sent
between service providers, introducing the system adopted by the
Italian government for the exchange of certified emails.
1.2. Notational Conventions
1.2.1. Requirement Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [REQ].
1.2.2. Acronyms
CMS: Cryptographic Message Syntax
CNIPA: Italian National Agency for Digital Administration
(Centro Nazionale per l'Informatica nella Pubblica
Amministrazione)
CNR: Italian National Research Council (Consiglio Nazionale
delle Ricerche)
CRL: Certificate Revocation List
CRL DP: Certificate Revocation List Distribution Point
DNS: Domain Name Service
DTD: Document Type Definition
FQDN: Fully Qualified Domain Name
ISTI: The Institute of Information Science and Technologies
at the CNR (Istituto di Scienza e Tecnologie
dell'Informazione "A.Faedo")
LDAP: Lightweight Directory Access Protocol
LDIF: LDAP Data Interchange Format
MIME: Multipurpose Internet Mail Extensions
PEC: Certified Electronic Mail (Posta Elettronica
Certificata)
S/MIME: Secure/MIME
SMTP: Simple Mail Transfer Protocol
TLS: Transport Layer Security
XML: eXtensible Markup Language
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1.2.3. Terminology and Definitions
Certification data: A set of data certified by the sender's PEC
provider that describes the original message. It includes the date
and time of dispatch, sender email address, recipient(s) email
address(es), subject, and message identifier.
Certified electronic mail: A service based on electronic mail, as
defined by the [EMAIL] and [SMTP] standards and extensions, which
permits the transmission of documents produced with informatics
tools.
DigitPA: Ex-CNIPA.
Holder: The person or organization to whom a PEC mailbox is assigned.
Message sent: A PEC message is considered sent when the sender's PEC
provider, after several checks, accepts the email and returns a
server-user acceptance PEC notification to the sender.
Message received: A PEC message is considered received when it is
stored in the receiver's mailbox, after which the receiver PEC
provider returns a delivery PEC notification to the sender.
Msgid: Is the message identifier generated by the email client, as
defined in [EMAIL], before the message is submitted to the PEC
system.
Ordinary mail: Non-PEC email messages.
Original message: Is the user-generated message before its arrival to
the sender Access Point. The original message is delivered to the
recipient inside a PEC transport envelope.
PEC domain: Corresponds to a DNS domain dedicated to the holders'
mailboxes.
PEC mailbox: An electronic mailbox for which delivery PEC
notifications are issued upon reception of PEC messages. Such a
mailbox can be defined exclusively within a PEC domain.
PEC msgid: Is a unique identifier generated by the PEC system, which
will substitute the msgid.
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PEC provider: The entity that handles one or more PEC domains with
their relative points of Access, Reception, and Delivery. It is the
holder of the key that is used for signing PEC notifications and
envelopes, and it interacts with other PEC providers for
interoperability with other holders.
PEC provider's key: Is a key released by DigitPA to every PEC
provider. It is used to sign PEC notifications and envelopes and to
authorize access to the PEC providers directory.
PEC providers directory: Is an LDAP server positioned in an area
reachable by all PEC service providers. It constitutes the technical
structure related to the public list of PEC service providers and
contains the list of PEC domains and service providers with relevant
certificates.
Service mailbox: A mailbox for the sole use of the provider,
dedicated for the reception of server-server acceptance and virus
detection PEC notifications.
Time stamp: Digital evidence with which a temporal reference, that
can't be repudiated, is attributed to one or more documents.
2. PEC Model
2.1. System-Generated Messages
The PEC system generates messages in MIME format composed of a
descriptive textual part and other [MIME1] parts, the number and
content of which varies according to the type of message generated.
A system-generated message falls into one of the following
categories:
o Notifications;
o Envelopes.
The message is inserted in an S/MIME v3 structure in CMS format and
signed with the PEC provider's private key. The X.509v3 certificate
associated with the key MUST be included in the aforementioned
structure. The S/MIME format used to sign system-generated messages
is the "multipart/signed" format (.p7s), as described in section
3.4.3 of [SMIMEV3].
To guarantee the verifiability of signatures on as many mail clients
as possible, X.509v3 certificates used by certified email systems
MUST abide by the profile found in section 6.5.
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In order for the receiving mail client to verify the signature, the
sender address MUST coincide with the one indicated within the
X.509v3 certificate. For this mechanism, PEC transport envelopes
MUST indicate in the "From:" field a single author's address which is
different from the one contained in the original message. To allow
for better message usability by the receiving user, the author's mail
address in the original message is inserted as a "display name". For
example, a "From:" field such as:
From: "John Smith" <john.smith@domain.example.com>
would result in the following "From:" value in the respective PEC
transport envelope:
From: "On behalf of: john.smith@domain.example.com"
<certified-mail@provider.example.com>
Both "From:" and "Sender:" fields MUST contain the same value. In
order for replies to be correctly sent back to the proper
destination, the "Reply-To:" field in the PEC transport envelope MUST
contain the same unaltered value of the original message's
"Reply-To:" field. When it is not explicitly specified in the
original message, the system that generates the PEC transport
envelope creates it by extracting the information from the "From:"
field in the original message.
When PEC notifications are sent, the system MUST use the original
message sender's address as the destination address, as is specified
in the reverse path data of the SMTP protocol. PEC notifications
MUST be sent to the sender's PEC mailbox without taking into account
the "Reply-To:" field, which might be present in the original
message's header.
All system-generated PEC messages are identifiable for having a
specific header defined in PEC according to the type of message
generated.
To determine the certification data, the elements used for the actual
routing of the message are employed. In SMTP dialog phases, the
reverse path and forward path data ("MAIL FROM" and "RCPT TO"
commands) are thus considered certification data of both the sender
and the recipients, respectively. Addressing data present in the
message body ("To:" and "Cc:" fields) are used solely in order to
discriminate between primary and carbon copy recipients when
necessary; addressing data present in the "Bcc:" field MUST be
considered invalid by the system.
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2.1.1. Message Types
All system-generated messages inherit their header fields and values
from the original message, with extra fields added according to the
type of message generated.
2.1.1.1. PEC Notifications
They have the purpose of informing the sending user and interacting
providers of the progress the message is making within the PEC
network.
2.1.1.1.1. Success PEC Notifications
These notifications indicate an acknowledgment on the provider's side
for the reception or handling of a PEC message. More specifically,
it can indicate one of three situations: server-user acceptance,
server-server acceptance, or delivery.
Added header fields are:
o X-Ricevuta:
o X-Riferimento-Message-ID:
The field "X-Ricevuta:" indicates the type of PEC notification
contained in the message, whereas "X-Riferimento-Message-ID:"
contains the message identifier generated by the mail client (msgid).
Body contents differ according to notification type. This is
described more thoroughly in section 3.
o A server-user acceptance PEC notification informs the user that
his provider has accepted the message and will be taking care of
passing it on to the provider(s) of the addressee(s).
o A server-server acceptance PEC notification is an inter-provider
communication only, it MUST NOT be sent to the users. With this
notification, the receiving provider simply informs the sending
one that it has received a PEC message, and will take the
responsibility of forwarding it to the addressee(s). From then
on, the sender provider is no longer held responsible as to the
whereabouts of the message, but is limited to notifying its user
of the success or failure of delivery.
o Delivery PEC notifications take place as the final communication
of a transaction, indicating overall success in handing the
message over to the addressee(s).
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2.1.1.1.2. Delay PEC Notifications
Delay PEC notifications are sent out 12 hours after a message has
been dispatched from the sending provider, and no server-server
acceptance or delivery PEC notification has been received. These
have the sole purpose of notifying the user of the delay.
If another 12 hours go by without any sign of a server-server
acceptance or delivery PEC notification (amounting to a 24-hour
delay), another delay PEC notification is dispatched to the user
informing him of the possible delivery failure. The provider will
not keep track of the delay any further.
2.1.1.1.3. Failure PEC Notifications
They are sent when there is some error in transmission or reception.
More specifically, a failure PEC notification can indicate either a
formal-exception error or a virus detection.
Added header fields are:
o X-Ricevuta:
o X-Riferimento-Message-ID:
o X-VerificaSicurezza: [optional]
"X-Ricevuta:" and "X-Riferimento-Message-ID:" have the same role as
indicated in section 2.1.1.1.1 (Success Notifications).
"X-VerificaSicurezza:" (security verification) is an optional header
field, used for virus-related PEC notifications.
Body contents differ according to notification type. This is
described more thoroughly in section 3.
2.1.1.2. PEC Envelopes
Messages entering the PEC network are inserted within specific PEC
messages, called envelopes, before they are allowed to circulate
further within the network. These envelopes MUST inherit the
following header fields, along with their unmodified values, from the
message itself:
o Received:
o To:
o Cc:
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RFC 6109 Certified Electronic Mail April 2011
o Return-Path:
o Reply-To: (if present)
Depending on the type of message requesting admission into the PEC
network, it will be inserted in either a PEC transport envelope or a
PEC anomaly envelope. Distinction will be possible through the
addition of the "X-Trasporto:" header field.
2.2. Basic Structure
+-------------+ +------------+
| +--+ | | |
| |AP| | PEC | |
+----+ | +--+ | messages & | +---+ +--+ | +----+
|user|<-->| |<------------->| |InP| |DP| |<-->|user|
+----+ | +--+ +---+ | notifications | +---+ +--+ | +----+
| |DP| |InP| | | |
| +--+ +---+ | | |
+-------------+ +------------+
PEC PEC
sender receiver
provider provider
where:
AP = Access Point
DP = Delivery Point
InP = Incoming Point
2.2.1. Access Point
This is what the user client at the sender side interacts with,
giving the user access to PEC services set up by the provider.
Such access MUST be preceded by user authentication on the system
(see section 5.2). The Access Point receives the original messages
its user wishes to send, runs some formal checks, and acts according
to the outcome:
o if the message passes all checks, the Access Point generates a
server-user acceptance PEC notification and inserts the original
message inside a PEC transport envelope;
o if a formal exception is detected, the Access Point refuses the
message and emits the relevant non-acceptance PEC notification
(see section 3.1.1);
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o if a virus is detected, the Access Point generates a non-
acceptance PEC notification and inserts the original message as is
in the provider's special store.
Generation of the server-user acceptance notification indicates to
the user that the message was accepted by the system, certifying also
the date and time of the event. The notification MUST contain user-
readable text, and an XML part containing the certification data.
The notification MAY also contain other attachments for extra
features offered by the provider.
Using the data available in the PEC providers directory (see section
4.5), the Access Point runs checks on every recipient in the "To:"
and "Cc:" fields present in the original message to verify whether
they belong to the PEC infrastructure or to non-PEC domains. Such
checks are done by verifying the existence, through a case-
insensitive search, of the recipients' domains in the
"managedDomains" attribute found within the PEC providers directory.
Therefore, the server-user acceptance PEC notification (and relevant
certification data) relates to, for each address, the typology of its
domain; PEC or non-PEC.
The message identifier (PEC msgid) of accepted original messages
within the PEC infrastructure MUST be unambiguous in order to consent
correct tracking of messages and relative PEC notifications. The
format of such an identifier is:
[alphanumeric string]@[provider mail domain]
or:
[alphanumeric string]@[FQDN mail server]
Therefore, both the original message and the corresponding PEC
transport envelope MUST contain the following header field:
Message-ID: <[unique identifier]>
When an email client that is interacting with the Access Point has
already inserted a message identifier (msgid) in the original
message, that msgid SHALL be substituted by a PEC msgid. In order to
allow the sender to link the message sent with the relative PEC
notifications, the msgid MUST be inserted in the original message as
well as the relative PEC notifications and transport envelope. If
present, the msgid is REQUIRED in the original message's header by
adding the following header field:
X-Riferimento-Message-ID: <[msgid]>
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which will also be inserted in the PEC transport envelope and
notifications, and related in the certification data (see section
4.4).
2.2.2. Incoming Point
This point permits the exchange of PEC messages and notifications
between PEC providers. It is also the point through which ordinary
mail messages can be inserted within the system of certified mail.
The exchange of messages between providers takes place through SMTP-
based transactions, as defined in [SMTP]. If SMTP communication
errors occur, they MAY be handled using the standard error
notification mechanisms, as provided by SMTP in [SMTP] and
[SMTP-DSN]. The same mechanism is also adopted for handling
transitory errors, that result in long idling periods, during an SMTP
transmission phase. In order to guarantee that an error is returned
to the user, as defined in section 3.3.3, the system that handles PEC
traffic MUST adopt a time limit for message idleness equal to 24
hours.
Once a message arrives, the Incoming Point runs the following list of
checks and operations:
o verifies correctness and type of the incoming message;
o if the incoming message is a correct and undamaged PEC transport
envelope:
- emits a server-server acceptance PEC notification towards the
sender provider (section 3.2.1);
- forwards the PEC transport envelope to the Delivery Point
(section 3.3).
o if the incoming message is a correct and undamaged PEC
notification, forwards the notification to the Delivery Point.
o if the incoming message does not conform to the prerequisites of a
correct and undamaged PEC transport envelope or notification, but
comes from a PEC provider, i.e., passes the verifications
regarding existence, origin, and validity of the signature, then
the message MUST be propagated towards the recipient.
Therefore, the Incoming Point:
- inserts the incoming message in a PEC anomaly envelope (section
3.2.2);
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- forwards the PEC anomaly envelope to the Delivery Point.
o if the incoming message does not originate from a PEC system,
i.e., fails verifications regarding existence, origin, and
validity of the signature, then the message will be treated as
ordinary email, and, if propagated to the recipient:
- is inserted in a PEC anomaly envelope (section 3.2.2);
- the PEC anomaly envelope is forwarded to the Delivery Point.
The server-server acceptance PEC notification is generated by the
receiving provider and sent to the sending provider. Its purpose
is to keep track of the message in its transition from one
provider to another, and is therefore strictly intra-provider
communication; the end user knows nothing about it.
To check the correctness and integrity of a PEC transport envelope
or notification, the Incoming Point runs the following tests:
o Signature existence - the system verifies the presence of an
S/MIME signature structure within the incoming message;
o Signature origin - the system verifies whether or not the
signature belongs to a PEC provider by extracting the certificate
used for signing and verifying its presence in the PEC providers
directory. To ease the check, it is possible to calculate the
certificate's [SHA1] hash value and perform a case-insensitive
search of its hexadecimal representation within the
"providerCertificateHash" attribute found in the PEC providers
directory. This operation allows one to easily identify the
sender provider for subsequent and necessary matching checks
between the extracted certificate and the one present in the
provider's record;
o Signature validity - S/MIME signature correctness is verified by
recalculating the signature value, checking the entire
certification path, and verifying the [CRL] and temporal validity
of the certificate. In case some caching mechanism is used for
CRL contents, an update interval MUST be adopted so that the most
up-to-date data is guaranteed, thus minimizing the possible delay
between a publication revocation by the Certification Authority
and the variation acknowledgment by the provider;
o Formal correctness - the provider performs sufficient and
necessary checks to guarantee that the incoming message is
compliant with the formats specified in this document (PEC
transport envelope and notifications).
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If a virus-infected PEC transport envelope passes the checks just
mentioned, it is still considered correct and undamaged. The
presence of the virus will be detected in a second phase, during
which the contents of the PEC transport envelope are verified.
Thus, the Incoming Point will refrain from forwarding the message
to the recipient, instead sending the appropriate PEC notification
of non-delivery and storing the virus-infected message in the
provider's special storage.
In case ordinary mail messages are received, the PEC provider
SHALL perform virus checks in order to prevent the infiltration of
potentially dangerous mail messages within the PEC system. If a
virus is detected in an ordinary mail message, the latter can be
discarded at the Incoming Point before it enters the PEC system.
In other words, no special treatment is reserved for the error; it
is handled in a manner that is conformant to the procedures
usually followed for messages going through the Internet.
When the receiving provider detects a virus inside a PEC transport
envelope during the reception phase, it emits a virus detection
PEC notification to the sending provider, which then realizes its
checks failed to detect that virus. When this happens, the
sending provider MUST:
o check what virus typologies were not detected by its own antivirus
to verify the possibility of interventions
o send a virus-induced non-delivery PEC notification to the sender's
mailbox.
2.2.3. Delivery Point
This point is the point that receives messages from the Incoming
Point and forwards them to the final recipient.
It MUST run a series of tests on received messages before forwarding
them to the user (see section 3.3.1). It first verifies the typology
of the message and decides whether or not a PEC notification should
be issued to the sender. The delivery PEC notification (section
3.3.2) is emitted after the message was delivered to the recipient's
PEC mailbox and only at reception of a valid PEC transport envelope
(sections 2.2.2 and 3.1.5).
In all other cases, such as PEC anomaly envelopes and PEC
notifications, the delivery PEC notification is not emitted.
Regardless, the message received from the Delivery Point MUST be
delivered unmodified to the recipient's mailbox.
Petrucci, et al. Informational [Page 16]RFC 6109 Certified Electronic Mail April 2011
The delivery PEC notification indicates to the sender that the
message sent was in fact conveyed to the specified recipient's
mailbox and certifies the date and time of delivery through use of
user-readable text and an XML part containing certification data,
along with other possible attachments added for extra features
offered by the provider.
If a PEC transport envelope received at the Delivery Point can't be
delivered to the destination mailbox, the Delivery Point emits a non-
delivery PEC notification (section 3.3.3). If, on the other hand,
the delivery error concerns a message that arrives from Internet
(i.e., a non-PEC message), no such notification is emitted.
2.2.4. Storage
Each provider MUST dedicate a special storage for the deposition of
any virus-infected messages encountered. Whether the virus be
detected by the sender's Access Point or the receiver's Incoming
Point, the provider that detects it MUST store the mail message in
its own storage, and keep it for 30 months.
2.2.5. Provider Service Mailbox
For exclusive use of the provider, dedicated to the reception of PEC
notifications in two cases only:
o server-server acceptance notification; and
o virus detection notification.
2.2.6. Provider Service Email Address
Each provider MUST register a special purpose email address for use
when sending PEC transport envelopes and notifications, as delineated
in section 3. This address MAY coincide with that of the service
mailbox described in section 2.2.5.
2.3. Log
The server administrator MUST keep track of any and all operations
carried out in a specific message log file. The information kept in
the log for each operation is the following:
o message identifier (msgid)
o date and time of event
o sender of original message
Petrucci, et al. Informational [Page 17]
RFC 6109 Certified Electronic Mail April 2011
o recipient(s) of original message
o subject of original message
o event type (reception, delivery, PEC notification emission, etc.)
o message identifiers of related generated messages
o sending provider
The service provider MUST store this data and preserve it unmodified.
Italian laws have specified that the service provider retain the data
for 30 months.
3. Message Processing
3.1. Access Point
The Access Point acts as a submission service as defined in
[SUBMISSION].
3.1.1. Formal Checks on Messages
When the Access Point receives a message the user wishes to send, it
MUST guarantee said message's formal conformity as defined in
[EMAIL], and verify that the:
o [EMAIL] header section contains a "From:" header field holding an
[EMAIL] compliant email address;
o [EMAIL] header section contains a "To:" header field holding one
or more [EMAIL] compliant email addresses;
o sender's address, specified in the SMTP reverse path, coincides
with the one in the message's "From:" header field;
o recipients' addresses specified in the SMTP forward path coincide
with the ones present in the "To:" or "Cc:" header fields of the
message;
o "Bcc:" header field does not contain any value;
o total message size falls within the limits accepted by the
provider. Such limits apply depending on the number of recipients
as well; by multiplying it to the message size, the outcome MUST
fall within the limits accepted by the provider. Italian laws
have specified this limit as being 30 MB.
Petrucci, et al. Informational [Page 18]RFC 6109 Certified Electronic Mail April 2011
If the message does not pass the tests, the Access Point MUST NOT
accept the message within the PEC system, thus emitting the relative
PEC notification of non-acceptance.
3.1.2. Non-Acceptance PEC Notification Due to Formal Exceptions
When the Access Point cannot forward the message received due to
failure in passing formal checks, the sender is notified of such an
outcome. If the error is caused by the message failing size checks,
a non-acceptance PEC notification is sent as long as the size remains
bound by a certain limit. If the size exceeds said limit, error
handling is left to SMTP.
The notification header will contain the following fields:
X-Ricevuta: non-accettazione
Date: [date of notification emission]
Subject: AVVISO DI NON ACCETTAZIONE: [original subject]
From: posta-certificata@[mail domain]
To: [original sender]
X-Riferimento-Message-ID: [msgid]
The notification body will contain a text part that constitutes the
actual notification in readable format according to a model that
relates the following information:
Error in message acceptance
On [date] at [time] ([time zone]), in the message "[subject]"
originating from "[original sender]" and addressed to:
[recipient_1]
[recipient_2]
[recipient_n]
a problem was detected that prevents its acceptance due to
[error description].
The message was not accepted.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification information is inserted in an XML file to be
added to the notification body, thus allowing automatic checks on the
message (section 4.4). Parsing MUST be done on the XML part only.
Additional parts MAY be included by the provider for provider-
specific services. Regardless, the original message MUST NOT be
included. The message MUST follow the format described in section
4.3.
Petrucci, et al. Informational [Page 19]RFC 6109 Certified Electronic Mail April 2011
3.1.3. Non-Acceptance PEC Notification Due to Virus Detection
The Access Point MUST run some tests on the content of messages it
receives from its users and reject them if a virus is detected. In
which case, a virus-detection-induced non-acceptance PEC notification
MUST be emitted to clearly inform the user of the reason the message
was refused.
The notification header contains the following fields:
X-Ricevuta: non-accettazione
X-VerificaSicurezza: errore
Date: [notification emission date]
Subject: AVVISO DI NON ACCETTAZIONE PER VIRUS: [original
subject]
From: posta-certificata@[mail domain]
To: [original sender]
X-Riferimento-Message-ID: [msgid]
The body contains a readable text part according to the following
model:
Error in message acceptance due to virus presence
On [date] at [time] ([time zone]), in the message "[subject]"
originating from "[original sender]" and addressed to:
[recipient_1]
[recipient_2]
[recipient_n]
a security problem was detected [ID of detected content type].
The message was not accepted.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file added to the
notification to allow for automatic checks (section 4.4). Parsing
MUST be done on the XML part only. Additional parts MAY be included
by the provider for provider-specific services. Regardless, the
original message MUST NOT be included. The message MUST follow the
format described in section 4.3.
3.1.4. Server-User Acceptance PEC Notification
The server-user acceptance PEC notification is a message sent to the
sender by his server, containing date and time of message acceptance
into the system, sender and recipient data, and subject.
Petrucci, et al. Informational [Page 20]RFC 6109 Certified Electronic Mail April 2011
The header contains the following fields:
X-Ricevuta: accettazione
Date: [actual date of server-user acceptance]
Subject: ACCETTAZIONE: [original subject]
From: posta-certificata@[mail domain]
To: [original sender]
X-Riferimento-Message-ID: [msgid]
The message body contains a text part that constitutes the
notification in readable format, according to a model that relates
the following information:
Server-User Acceptance PEC notification
On [date] at [time] ([time zone]), the message "[subject]"
originating from "[original sender]" and addressed to:
[recipient_1] (["certified mail" | "ordinary mail"])
[recipient_2] (["certified mail" | "ordinary mail"])
[recipient_n] (["certified mail" | "ordinary mail"])
was accepted by the system and forwarded to the recipient(s).
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file added to the
notification message, allowing automatic checks on it (section 4.4).
Parsing MUST be done on the XML part only. Additional parts MAY be
included by the provider for provider-specific services. The message
MUST follow the format described in section 4.3.
3.1.5. PEC Transport Envelope
A PEC transport envelope is a message generated by the Access Point
that contains the original message as well as certification data.
As mentioned in section 2.1.1.2, the PEC transport envelope inherits
from the original message the values of the following header fields,
which MUST be related unmodified:
o Received:
o To:
o Cc:
o Return-Path:
o Reply-To: (if present)
Petrucci, et al. Informational [Page 21]RFC 6109 Certified Electronic Mail April 2011
On the other hand, the following fields MUST be modified, or inserted
if necessary:
X-Trasporto: posta-certificata
Date: [actual date of server-user acceptance]
Subject: POSTA CERTIFICATA: [original subject]
From: "On behalf of: [original sender]"
<certified-mail@[mail_domain]>
Reply-To: [original sender] (inserted only if not present)
Message-ID: [PEC msgid generated as in section 2.2.1]
X-Riferimento-Message-ID: [msgid]
X-TipoRicevuta: [completa/breve/sintetica]
The "X-TipoRicevuta:" field indicates the type of delivery PEC
notification the sender wishes to receive -- complete, brief, or
concise.
The body of the PEC transport envelope contains a text part that
constitutes the readable format of the message according to a model
that relates the following certification data:
Certified mail message
On [date] at [time] ([time zone]), the message "[subject]" was
sent by "[original sender]" and addressed to:
[recipient_1]
[recipient_2]
[recipient_n]
The original message is included in attachment.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
Within the PEC transport envelope, the entire, non-modified original
message is inserted in a format compliant with [EMAIL] (except for
what has been said regarding the message identifier), as well as an
XML part, which contains the certification data that was already
related in text format, and information on the type of message and
PEC notification requested (section 4.4). Parsing MUST be done on
the XML part only. Additional parts MAY be included by the provider
for provider-specific services. The message MUST follow the format
described in section 4.3.
Note that the routing data of the PEC transport envelope (forward and
reverse paths) remain unaltered.
Petrucci, et al. Informational [Page 22]RFC 6109 Certified Electronic Mail April 2011
3.1.6. Timeout Delivery Error PEC Notification
If the sending provider doesn't receive a server-server acceptance or
delivery PEC notification from the receiving provider within 12 hours
of the message dispatch, it informs the user that the recipient's
provider might not be able to deliver the message. In case the
sending provider doesn't receive a delivery PEC notification within
24 hours after message dispatch, it emits another non-delivery PEC
notification to the user by the 24-hour timeout, but not before 22
hours have passed.
Such a communication takes place through a PEC notification of non-
delivery due to timeout, the header of which contains the following
fields:
X-Ricevuta: preavviso-errore-consegna
Date: [date of notification emission]
Subject: AVVISO DI MANCATA CONSEGNA PER SUP. TEMPO MASSIMO:
[original subject]
From: posta-certificata@[mail domain]
To: [original recipient]
X-Riferimento-Message-ID: [msgid]
The body of the first non-delivery PEC notification (12-hour timeout)
contains a text part that represents the readable format of the
notification which will relate the following data:
Non-delivery PEC notification
On [date] at [time] ([time zone]), the message
"[subject]" originating from "[original sender]"
and addressed to "[recipient]"
has not been delivered within the first 12 hours following
its dispatch. Not excluding that the message might eventually
be delivered, it is deemed useful to consider that dispatch
might not have a positive outcome. The system will see to
sending another non-delivery PEC notification if in the
following twelve hours no confirmation is received from the
recipient.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
On the other hand, 24-hour-timeout induced PEC notifications, which
have the same header as described above, will have the following text
in their body:
Petrucci, et al. Informational [Page 23]RFC 6109 Certified Electronic Mail April 2011
Non-delivery PEC notification
On [date] at [time] ([time zone]), the message
"[subject]" originating from "[original sender]"
and addressed to "[recipient]"
has not been delivered within 24 hours of its dispatch.
The transaction is deemed to be considered terminated with a
negative outcome.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file added to both
PEC notification types to allow automatic checks (section 4.4).
Parsing MUST be done on the XML part only. Additional parts MAY be
added for services supplied by the PEC provider. Regardless, the
original message MUST NOT be included. The message MUST follow the
format described in section 4.3.
A timeout PEC notification is generated if one of the following
scenarios occurs:
o the sending provider receives a server-server acceptance PEC
notification during the first 12 hours following message dispatch,
but does not receive a delivery PEC notification at all. In this
case, it would be a 24-hour timeout PEC notification.
o the sending provider does not receive a server-server acceptance
PEC notification, but receives a delivery PEC notification after
12 hours and before the 24-hour timeout. In this case it would be
a 12-hour timeout PEC notification.
o the sending provider doesn't receive either a server-server
acceptance or a delivery PEC notification. In this case, two
timeout PEC notifications are generated; a 12-hour and a 24-hour
timeout PEC notification.
3.2. Incoming Point
3.2.1. Server-Server Acceptance PEC Notification
When correct PEC transport envelopes (as defined in section 2.2.2.)
are exchanged between PEC providers, the receiver MUST send a server-
server acceptance PEC notification to the sender. The single
dispatched notification concerns all recipients who belong to the
same provider, and to whom the incoming message was addressed, as
stated in the routing data (forward and reverse paths) of the SMTP
transaction. Within the certification data of a single server-server
Petrucci, et al. Informational [Page 24]RFC 6109 Certified Electronic Mail April 2011
acceptance PEC notification, all recipients of the message to which
it refers are listed. In general, when receiving a PEC transport
envelope, each provider MUST emit one or more server-server
acceptance PEC notifications to cover, in absence of SMTP transport
errors, all the recipients in its jurisdiction.
The header of a server-server acceptance PEC notification contains
the following fields:
X-Ricevuta: presa-in-carico
Date: [date of server-server acceptance]
Subject: PRESA IN CARICO: [original subject]
From: posta-certificata@[mail domain]
To: [sender provider service mailbox]
X-Riferimento-Message-ID: [msgid]
The provider's service email address is obtained from the PEC
providers directory during the necessary queries made in the
signature verification stage.
The body contains a text part that follows the underlying model:
Server-server acceptance PEC notification
On [date] at [time] ([time zone]), the message "[subject]"
originating from "[original sender]" and addressed to:
[recipient_1]
[recipient_2]
[recipient_n]
was accepted by the system.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file which is added
to the notification message to allow for automatic checks (section
4.4). Parsing MUST be done on the XML part only. Additional parts
MAY be added by the provider for provider-specific services. The
message MUST follow the format described in section 4.3.
3.2.2. PEC Anomaly Envelope
If the tests on an incoming message detect an error, or the message
is identified as being ordinary mail and the provider is set to
forward it to the recipient, the system MUST insert such a message in
a PEC anomaly envelope. Before delivery, the entire message received
Petrucci, et al. Informational [Page 25]RFC 6109 Certified Electronic Mail April 2011
at the Incoming Point is inserted in a format compliant with [EMAIL]
as a [MIME1] part inside a new message that MUST inherit the
unmodified values for the following header fields from the received
message:
o Received:
o To:
o Cc:
o Return-Path:
o Message-ID:
Whereas, the following header fields MUST be modified or inserted:
X-Trasplorto: errore
Date: [mlessage arrival date]
Subject: ANOMALIA MESSAGGIO: [original subject]
From: "On behalf of: [original sender]"
<posta-certificata@[mail_domain]>
Reply-To: [original sender (inserted only if not already
present)]
The body contains a user-readable text part according to a model that
relates the following data:
Message anomaly
On [date] at [time] ([time zone]), the message "[subject]"
originating from "[original sender]" and addressed to:
[recipient_1]
[recipient_2]
[recipient_n]
was received.
The data has not been certified due to the following error:
[concise description of error]
The original message is attached.
Due to uncertainty regarding origin and/or conformity of the message
received, the PEC anomaly envelope MUST NOT contain [MIME1] parts
other than the entire message that arrived at the Incoming Point.
Note that the routing data of such an envelope (forward and reverse
paths) remain unaltered. Doing so guarantees both message forwarding
to the recipients, and reception of SMTP error notifications, if any
occur, by the sender (as specified in [SMTP] and [SMTP-DSN]).
Petrucci, et al. Informational [Page 26]RFC 6109 Certified Electronic Mail April 2011
3.2.3. Virus Detection PEC Notification
If the Incoming Point receives virus-infected PEC messages, it MUST
NOT forward them. Rather it MUST inform the sending provider, which
will in turn inform the sending user, of the failed transmission. A
separate PEC notification of virus detection MUST be sent on behalf
of every recipient within the provider's domain.
In case a virus is detected during the reception phase of a message
whose origin was asserted through sender signature verification, the
system generates a virus-detected PEC notification indicating the
error found, and sends it to the sending provider's service mailbox.
The header of this PEC notification contains the following fields:
X-Ricevuta: rilevazione-virus
X-Mittente: [original sender]
Date: [date of notification emission]
Subject: PROBLEMA DI SICUREZZA: [original subject]
From: posta-certificata@[mail domain]
To: [sender provider notifications]
X-Riferimento-Message-ID: [msgid]
The body contains a readable text part according to a model that
relates the following data:
Virus detection PEC notification
On [date] at [time] ([time zone]), in the message "[subject]"
originating from "[original sender]" and addressed to
"[recipient]"
a security problem was detected [ID of content type detected].
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file and added to
the notification to allow for automatic checks (section 4.4).
Parsing MUST be done on the XML part only. Additional parts MAY be
included by the provider for provider-specific services. Regardless,
the original message MUST NOT be included. The message MUST follow
the format described in section 4.3.
The message body MUST contain the reason for which the transmission
could not be completed.
Petrucci, et al. Informational [Page 27]RFC 6109 Certified Electronic Mail April 2011
3.2.4. Virus-Induced Delivery Error PEC notification
At the reception of a virus detection PEC notification from the
receiving provider, the sender provider emits a non-delivery PEC
notification to the sending user.
The header for this notification contains the following fields:
X-Ricevuta: errore-consegna
X-VerificaSicurezza: errore
Date: [date of notification emission]
Subject: AVVISO DI MANCATA CONSEGNA PER VIRUS: [original
subject]
From: posta-certificata@[mail domain]
To: [original sender]
X-Riferimento-Message-ID: [msgid]
The body contains a readable text part according to a model that
relates the following data:
Delivery error PEC notification due to virus
On [date] at [time] ([time zone]), in the message "[subject]"
addressed to "[recipient]"
a security problem was detected [ID of content type detected
by the anti-virus].
The message was not delivered.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
All the information necessary for the construction of such a PEC
notification can be obtained from the correlated virus-detected PEC
notification.
The same certification data is inserted in an XML file and added to
the notification message to allow for automatic checks (section 4.4).
Parsing MUST be done on the XML part only. Additional parts MAY be
included by the provider for provider-specific services. The reason
the transaction was not completed MUST be specified in the message,
which MUST follow the format described in section 4.3.
Petrucci, et al. Informational [Page 28]RFC 6109 Certified Electronic Mail April 2011
3.3. Delivery Point
3.3.1. Checks on Incoming Messages
When a message arrives at the Delivery Point, the system verifies:
o message type
o whether or not a PEC notification has to be returned.
3.3.2. Delivery PEC Notification
A delivery PEC notification is issued only after a correct PEC
transport envelope (sections 2.2.2 and 3.1.5) has been delivered to
the recipient's mailbox.
In all other cases (e.g., PEC anomaly envelopes, PEC notifications),
the delivery PEC notification is not issued. Regardless, the message
received at the Delivery Point MUST be delivered to the recipient's
mailbox unchanged.
This notification tells the user that his/her message has been
successfully delivered to the specified recipient. It includes
readable text that certifies the date and time of delivery, sender
and receiver data, and the subject. It also contains an XML
certification data file and other optional parts for functionalities
offered by the provider.
The following fields are inserted in the header:
X-Ricevuta: avvenuta-consegna
Date: [delivery date]
Subject: CONSEGNA: [original subject]
From: posta-certificata@[mail domain]
To: [original sender]
X-Riferimento-Message-ID: [msgid]
The value of the "X-TipoRicevuta:" header field in the PEC transport
envelope is derived from the original message, thus allowing the
sender to determine the type of delivery PEC notification requested
from the primary recipients of the original message. The
notification MUST follow the format described in section 4.3.
3.3.2.1. Delivery PEC Notification: Complete
This is the default value for delivery PEC notifications. When no
value for "X-TipoRicevuta:" is specified, or when it contains the
value "completa" (complete), the system will require a complete
Petrucci, et al. Informational [Page 29]RFC 6109 Certified Electronic Mail April 2011
delivery PEC notification from addressees in the "To:" field, while a
concise PEC notification (section 3.3.2.3) will be required from
those in the "Cc:" field. The distinction between primary recipients
and those in carbon copy is done through an analysis of the "To:" and
"Cc:" fields. For PEC notifications sent on behalf of primary
recipients, a complete copy of the original message along with any
attachments is inserted in the notification. In case the system in
charge of delivery is not able to determine the recipient type due to
ambiguity problems in the "To:" and "Cc:" fields, delivery MUST be
considered as if addressed to a primary recipient and include the
complete copy of the original message.
The notification body contains a readable text part that relates
certification data according to the following model:
Delivery PEC notification
On [date] at [time] ([time zone]), the message "[subject]"
originating from "[original sender]" and addressed to
"[recipient]"
was placed in the destination's mailbox.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file and added to
the notification (section 4.4), along with any other parts that MAY
be inserted by the provider for provider-specific services. Parsing
MUST be done on the XML part only. The delivery PEC notification
MUST be issued on behalf of every recipient of the message, and MUST
follow the format described in section 4.3.
3.3.2.2. Delivery PEC Notification: Brief
In order to decrease the amount of data flowing, it is possible for
the sender to ask for a delivery PEC notification in "brief" format.
The brief delivery PEC notification contains the original message and
a ciphered hash value for each of its parts. The hash value SHOULD
be calculated on base64 encoded parts. As specified in section 5.3,
PEC messages MUST transit only on machines that belong to the PEC
network and that MUST NOT alter the encoding of the message during
its transition/processing.
NOTE: Even though PEC uses these relaxed specifications, PEC
interoperability tests between over 20 service providers have never
revealed any problems. This is probably due to mail servers leaning
more towards leaving the messages they receive intact without
Petrucci, et al. Informational [Page 30]RFC 6109 Certified Electronic Mail April 2011
applying any changes. But issues might arise if a server decides to
modify encoded parts; for example, change the base64 line length,
whose hash value calculated at the receiver's end would then differ
from that at the sender's side.
To be able to verify the transmitted contents it is necessary for the
sender to keep the unaltered original copy of the part(s) to which
the hash values refer.
If the PEC transport envelope contains the header:
X-TipoRicevuta: breve
the Delivery Point emits a brief delivery PEC notification on behalf
of the primary recipients, and a concise one (section 3.3.2.3) on
behalf of carbon copy recipients. The value of the header field in
the PEC transport envelope is derived from the original message.
The notification body contains a readable text part according to a
model that relates the following certification data:
Brief delivery PEC notification
On [date] at [time] ([time zone]), the message "[subject]"
originating from "[original sender]" and addressed to
"[recipient]"
was placed in the destination's mailbox.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted in an XML file and added to
the notification (section 4.4), along with other parts that MAY be
included for specific provider-supplied services. Parsing MUST be
done on the XML part only. The delivery PEC notification is issued
on behalf of every recipient of the message, and MUST follow the
format described in section 4.3.
The MIME structure of the original message is unaltered as it is
added to the notification, but each MIME part with a "name" parameter
in the header field "Content-Type:" or a "filename" parameter in the
header field "Content-Disposition:" MUST be substituted by a text
file containing that MIME part's hash value.
When the original message has an S/MIME format, it is necessary not
to alter the integrity of the message structure. Verification of the
S/MIME part in the original message takes place when the MIME type of
the top-level entity (which coincides with the message itself) is
checked. An S/MIME message MAY have the following MIME types (as per
[SMIMEV3]):
Petrucci, et al. Informational [Page 31]RFC 6109 Certified Electronic Mail April 2011
o multipart/signed
Represents an original message signed by the sender using the
structure described in [MIME-SECURE]. The message is made up of
two MIME parts: the first is the message itself before the
application of the sender's signature, whereas the second contains
signature data. The second part (generally of type
"application/pkcs7-signature" or "application/x-pkcs-signature")
contains data added during the signing phase and MUST be left
unchanged to avoid compromising the overall message structure;
o "application/pkcs7-mime" or "application/x-pkcs7-mime"
The message is composed of a sole CMS object within the MIME part.
Given that attachments cannot be separated from the CMS object,
the MIME part is left intact (i.e., it is not replaced by the hash
value); therefore, the brief PEC notification is the same as the
complete PEC notification.
If the original message contains parts whose "Content-Type:" is
"message/rfc822", i.e., contains an email message as attachment, the
entire attached message is substituted with its corresponding hash
value.
Therefore, when emitting a brief delivery PEC notification, the
provider MUST:
1. identify and extract all the parts from the first MIME part of the
multipart/signed S/MIME message;
2. calculate the hash values of all the files attached by the sender
to the original message;
3. substitute originals with their hash values.
In general, in the case of original messages in S/MIME format, the
copy of the message inserted within the brief delivery PEC
notification will have the following characteristics:
o if the original message is signed, the S/MIME structure and
signature-relative data will remain unchanged. The message will
generate an error in a future signature integrity verification
phase following the substitution of attachments with the
corresponding hash values.
o if the original message contains the "application/pkcs7-mime" or
"application/x-pkcs7-mime" MIME type, attachments present in the
message will not be substituted by their hash values, due to
Petrucci, et al. Informational [Page 32]RFC 6109 Certified Electronic Mail April 2011
impossibility of identification within a CMS structure. The
content of the brief delivery PEC notification will coincide with
that of a normal delivery PEC notification.
The algorithm used for hash calculation is the [SHA1], calculated on
the entire content of the part. To allow distinction between hash
files and the files to which they refer, the suffix ".hash" is added
to the original filename. The hash value is written in the file
using a hexadecimal representation as a single sequence of 40
characters. The MIME type of these attachments is set to
"text/plain" to highlight their textual nature.
3.3.2.3. Delivery PEC Notification: Concise
If the PEC transport envelope contains the header:
X-TipoRicevuta: sintetica
the Delivery Point emits, both to primary and carbon copy recipients,
a concise delivery PEC notification that does not contain the
original message.
The message body of the notification contains a readable text part
according to a model that relates the following certification data:
Concise delivery PEC notification
On [date] at [time] ([time zone]), the message "[subject]"
originating from "[original sender]" and addressed to
"[recipient]"
was placed in the destination's mailbox.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted within an XML file and added
to the notification (section 4.4), along with additional parts that
MAY be included for provider-specific services. Parsing MUST be done
on the XML part only. The notification is sent to each one of the
recipients to whom the message is delivered, and MUST follow the
format described in section 4.3.
The concise delivery PEC notification follows the same emission rules
as the delivery PEC notification; added to it is only the XML file
containing the certification data, not the original message.
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3.3.3. Non-Delivery PEC Notification
If an error occurs during the delivery of a correct PEC transport
message, the system returns to the sender a non-delivery PEC
notification that indicates the error condition.
The header will contain the following fields:
X-Ricevuta: errore-consegna
Date: [date of notification emission]
Subject: AVVISO DI MANCATA CONSEGNA: [original subject]
From: posta-certificata@[mail domain]
To: [original sender]
X-Riferimento-Message-ID: [msgid]
The notification body contains a readable text part according to a
model that relates the following data:
Non-delivery PEC notification
On [date] at [time] ([time zone]), in the message "[subject]"
originating from "[original sender]" and addressed to
"[recipient]"
an error was detected [brief error description].
The message was refused by the system.
Message identifier: [PEC msgid of corresponding
PEC transport envelope]
The same certification data is inserted within an XML file and added
to the notification in order to allow for automatic checks (section
4.4). Parsing MUST be done on the XML part only. Additional parts
MAY be included by the PEC provider for provider-specific services.
The notification MUST follow the format described in section 4.3.
3.4. Sender and Receiver Belonging to the Same Domain
PEC messages MUST be processed even if both sender and receiver(s)
belong to the same PEC domain.
3.5. Example: Complete Transaction between Two PEC Domains
A correct transaction between two PEC domains goes through the
following steps:
o The sending user sends an email to his provider's Access Point;
o The Access Point runs all checks and emits a server-user
acceptance PEC notification to the user;
Petrucci, et al. Informational [Page 34]RFC 6109 Certified Electronic Mail April 2011
o The Access Point creates a PEC transport envelope and forwards it
to the Incoming Point of the receiving provider;
o The receiver's Incoming Point verifies the PEC transport envelope
and creates a server-server acceptance PEC notification to be sent
to the sending provider;
o The sender's Incoming Point verifies the validity of the server-
server acceptance PEC notification and forwards it to the Delivery
Point;
o The sender's Delivery Point saves the server-server acceptance PEC
notification in the provider's service mailbox;
o The receiver's Incoming Point forwards the PEC transport envelope
to the receiver's Delivery Point;
o The receiver's Delivery Point verifies the contents of the PEC
transport envelope and saves it in the recipient's mailbox;
o The receiver's Delivery Point creates a delivery PEC notification
and sends it to the sender's Incoming Point;
o The sender's Incoming Point verifies the validity of the delivery
PEC notification and forwards it to the sender's Delivery Point;
o The sender's Delivery Point saves the delivery PEC notification in
the sending user's mailbox;
o The receiving user has the message at his disposition.
NOTE: Some of these steps might occur in parallel, thus the
interaction might complete in a different order.
4. Formats
4.1. Temporal Reference
For all operations carried out during message, notification, and log
elaboration processes by the Access, Incoming, and Delivery Points,
it is necessary to have an accurate temporal reference available.
All events (generation of PEC notifications, transport envelopes,
logs, etc.) that constitute the transaction of message elaboration at
the Access, Incoming, and Delivery Points MUST employ a sole temporal
value obtained from within the transaction itself.
Petrucci, et al. Informational [Page 35]RFC 6109 Certified Electronic Mail April 2011
Doing this renders the instant of message elaboration unambiguous
within PEC logs, notifications, messages, etc., generated by the
server.
4.2. User Date/Time
Temporal indications supplied by the service in readable format (text
in PEC notifications, transport envelopes, etc.) are provided with
reference to the legal time at the moment of the operation.
Following is the specification using the syntax description notation
defined in [ABNF].
date-fullyear = 4DIGIT
date-month = 2DIGIT ; 01-12
date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on
; month/year
time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59
time-second = 2DIGIT ; 00-58, 00-59, 00-60 based on leap second
; rules
time-offset = "(" ("+" / "-") time-hour ":" time-minute ")"
partial-time = time-hour ":" time-minute ":" time-second
full-date = date-mday "/" date-month "/" date-fullyear
full-time = partial-time time-offset
NOTE: For number of days in a month, leap year, and leap second
restrictions see section 5.7 of [TIMESTAMP].
4.3. Format of a PEC Message Body
This section describes the characteristics of the various components
of PEC messages and notifications generated by a PEC system. If one
of the message parts contains characters with values outside of the
range 0-127 (7-bit ASCII), that part will have to be adequately
encoded so that 7-bit transportation compatibility is guaranteed
(e.g., quoted-printable, base64 as per [MIME1]).
Before applying the signature, the message body has Content-Type:
multipart/mixed. Each part is described in the sections below. The
first part is the user readable text generated by the PEC system,
while the second and third parts are interchangeable in order and
contain the original message and the XML file for the certification
data.
Petrucci, et al. Informational [Page 36]RFC 6109 Certified Electronic Mail April 2011
4.3.1. User Readable Text
Character set: ISO-8859-1 (Latin-1)
MIME type: text/plain or multipart/alternative
The multipart/alternative MIME type MAY be used to add an HTML
version of the body of system-generated messages. In this case, two
sub-parts MUST be present: one of type text/plain, the other
text/html. For the HTML part:
o it MUST contain the same information as related in the text part;
o it MUST NOT contain references to elements (e.g., images, sounds,
font, style sheets), neither internal to the message (added MIME
parts) nor external (e.g., hosted on the provider's server);
o it MUST NOT have active content (e.g., JavaScript, VBscript, Plug-
in, ActiveX).
4.3.2. Original Message
MIME type: message/rfc822
Attachment name: postacert.eml
4.3.3. Certification Data
Character set: UTF-8
MIME type: application/xml
Attachment name: certdata.xml
4.4. Certification Data Scheme
Following is the DTD relative to the [XML] file that contains
certification data attached to PEC notifications.
<!--Use the element "postacert" as root-->
<!--"tipo" indicates the typology of the PEC message-->
<!--The attribute "errore" can have the following values-->
<!--"nessuno" = no error-->
<!--"no-dest" (with type="errore-consegna") = -->
<!-- wrong recipient-->
<!--"no-dominio" (with type="errore-consegna") = -->
<!-- wrong domain-->
<!--"virus" (with type="errore-consegna") = virus-->
<!--"virus" (with type="non-accettazione") = virus-->
<!--"altro" = generic error-->
<!ELEMENT postacert (intestazione, dati)>
<!ATTLIST postacert
Petrucci, et al. Informational [Page 37]RFC 6109 Certified Electronic Mail April 2011
tipo (accettazione |
non-accettazione |
presa-in-carico |
avvenuta-consegna |
posta-certificata |
errore-consegna |
preavviso-errore-consegna |
rilevazione-virus) #REQUIRED
errore (nessuno |
no-dest |
no-dominio |
virus |
altro) "nessuno">
<!--Header of the original message-->
<!ELEMENT intestazione (mittente,
destinatari+,
risposte,
oggetto?)>
<!--Sender ("From:" field) of the original message-->
<!ELEMENT mittente (#PCDATA)>
<!--Complete list of recipients ("To:" and "Cc:" fields)-->
<!--of the original message-->
<!--"tipo" indicates the typology of the recipient-->
<!ELEMENT destinatari (#PCDATA)>
<!ATTLIST destinatari
tipo (certificato | esterno) "certificato">
<!--Value of the "Reply-To:" field of the original message-->
<!ELEMENT risposte (#PCDATA)>
<!--Value of the "Subject:" field of the original message-->
<!ELEMENT oggetto (#PCDATA)>
<!--PEC message data-->
<!ELEMENT dati (gestore-emittente,
data,
identificativo,
msgid?,
ricevuta?,
consegna?,
ricezione*,
errore-esteso?)>
<!--Descriptive string of the provider that certifies -->
<!--the data-->
<!ELEMENT gestore-emittente (#PCDATA)>
Petrucci, et al. Informational [Page 38]RFC 6109 Certified Electronic Mail April 2011
<!--Date/time of message elaboration-->
<!--"zona" is the difference between local time and UTC in -->
<!--"[+|-]hhmm" format-->
<!ELEMENT data (giorno, ora)>
<!ATTLIST data
zona CDATA #REQUIRED>
<!--Day in "dd/mm/yyyy" format-->
<!ELEMENT giorno (#PCDATA)>
<!--Local hour in "hh:mm:ss" format-->
<!ELEMENT ora (#PCDATA)>
<!--PEC msgid-->
<!ELEMENT identificativo (#PCDATA)>
<!--msgid of the original message before modifications-->
<!ELEMENT msgid (#PCDATA)>
<!--For PEC transport envelopes and delivery notifications-->
<!--indicate the type of PEC notification requested by the-->
<!--sender-->
<!ELEMENT ricevuta EMPTY>
<!ATTLIST ricevuta
tipo (completa |
breve |
sintetica ) #REQUIRED>
<!--For delivery, non-delivery, virus-induced non-delivery, -->
<!-- virus detection, and timeout PEC notifications-->
<!--Recipient address to which delivery has been carried -->
<!--out/tried-->
<!ELEMENT consegna (#PCDATA)>
<!--For server-server acceptance PEC notifications-->
<!--recipients for whom it is the relative PEC notification-->
<!ELEMENT ricezione (#PCDATA)>
<!--In case of error-->
<!--brief description of the error-->
<!ELEMENT errore-esteso (#PCDATA)>
4.5. PEC Providers Directory Scheme
The PEC providers directory is created through a centralized LDAP
server that contains the providers' data and their corresponding PEC
mail domains.
Petrucci, et al. Informational [Page 39]RFC 6109 Certified Electronic Mail April 2011
The following are the directory scheme's attributes:
- providerCertificateHash: hash of provider's certificate
- providerCertificate: provider certificate
- providerName: provider name
- mailReceipt: provider reception email address
- managedDomains: managed domains
- LDIFLocationURL: provider LDIF record URL
- providerUnit: secondary operating environment name
The directory's base root is "o=postacert" and the
"DistinguishedName" of single records is of the type
"<providerName=<name>,o=postacert>". Search within the directory is
carried out mainly in case-sensitive mode using the
"providerCertificateHash" attribute (during envelope signature
verification phase) or the "managedDomains" attribute (during message
acceptance phase). It is possible for the record of a single
provider to contain multiple "providerCertificate" attributes with
the related "providerCertificateHash" attributes in order to allow
the handling of the renewal of expiring certificates. The provider
MUST make sure to update its record with sufficient advance before
the certificate expiration date, by adding a new certificate whose
validity overlaps that of the previous one.
The data of all PEC providers is encompassed in a [LDIF] file, which
is available as an [HTTPS] object and can be found at the URL to
which the 'LDIFLocationURL' attribute in the "dn: o=postacert" record
points (see section 4.5.6). To guarantee authenticity, that file
MUST be signed by the provider for the operations regarding its PEC
services using the method described for single providers. The file,
the signature, and the X.509v3 certificate MUST be inserted in a
PKCS#7 structure in binary ASN.1 DER format as a file with ".p7m"
extension. The centralized [LDAP] system downloads that file on a
daily basis and, after suitable verifications of the signature,
applies it to the provider's record.
Through the [LDIF] file, single providers MUST keep a copy of the
directory locally, updated on a daily basis, in order to improve
system performance by avoiding continuous request dispatches to the
central system for every message elaboration phase.
Petrucci, et al. Informational [Page 40]
RFC 6109 Certified Electronic Mail April 2011
If secondary environments are present, the [LDIF] file indicated in
the main environment's record MUST relate the contents of all the
provider-relevant records.
NOTE: This specification uses an unregistered LDAP DN name space
that may lead to conflict with other registered or
unregistered names.
4.5.1. providerCertificateHash Attribute
The 'providerCertificateHash' attribute is a hexadecimal
representation of the hash in SHA1 format of the X.509v3 certificate
used by the provider for PEC notifications and envelope signatures.
( 1.3.6.1.4.1.16572.2.2.1 NAME 'providerCertificateHash'
DESC 'Hash SHA1 of X.509 certificate in hexadecimal format'
EQUALITY caseIgnoreIA5Match
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )
The IA5String ( 1.3.6.1.4.1.1466.115.121.1.26 ) syntax is defined in
[LDAP-SYNTAXES].
4.5.2. providerCertificate Attribute
The 'providerCertificate' attribute holds a set of certificate(s)
used by the provider to sign PEC notifications and transport
envelopes.
( 1.3.6.1.4.1.16572.2.2.2 NAME 'providerCertificate'
DESC 'X.509 certificate in ASN.1 DER binary format'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.8 )
The Certificate syntax ( 1.3.6.1.4.1.1466.115.121.1.8 ) is defined in
[RFC4523].
As required by this attribute type's syntax, values of this attribute
are requested and transferred using the attribute description
"providerCertificate;binary" [RFC4522].
4.5.3. providerName Attribute
The 'providerName' attribute contains the name of the PEC provider.
All records MUST contain their provider's name in this attribute.
Petrucci, et al. Informational [Page 41]RFC 6109 Certified Electronic Mail April 2011
( 1.3.6.1.4.1.16572.2.2.3 NAME 'providerName'
DESC 'PEC provider name'
EQUALITY caseIgnoreMatch
SUBSTR caseIgnoreSubstringsMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
SINGLE-VALUE )
The Directory String ( 1.3.6.1.4.1.1466.115.121.1.15 ) syntax is
defined in [LDAP-SYNTAXES].
4.5.4. mailReceipt Attribute
The 'mailReceipt' attribute contains the provider's email address
within the provider to which server-server acceptance and virus
detection PEC notifications are sent. This address is a limited
version of the addr-spec construct described in [EMAIL] (without
angle brackets); it only permits the dot-atom-text form on both the
left- and right-hand sides of the "@", and does not have internal
CFWS.
( 1.3.6.1.4.1.16572.2.2.4 NAME 'mailReceipt'
DESC 'E-mail address of the service mailbox'
EQUALITY caseIgnoreIA5Match
SUBSTR caseIgnoreIA5SubstringsMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26
SINGLE-VALUE )
The IA5String ( 1.3.6.1.4.1.1466.115.121.1.26 ) syntax is defined in
[LDAP-SYNTAXES].
4.5.5. managedDomains Attribute
The 'managedDomains' attribute holds a set of domains [SMTP] that are
handled by a PEC provider. Domains are limited to dot-atom form
([RFC1034], [EMAIL]).
( 1.3.6.1.4.1.16572.2.2.5 NAME 'managedDomains'
DESC 'Domains handled by the PEC provider'
EQUALITY caseIgnoreIA5Match
SUBSTR caseIgnoreIA5SubstringsMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )
The IA5String ( 1.3.6.1.4.1.1466.115.121.26 ) syntax is defined in
[LDAP-SYNTAXES].
The 'managedDomains' attribute holds a set of domains [SMTP] that are
handled by a PEC provider. Domains are limited to dot-atom form
([RFC1034], [EMAIL]).
Petrucci, et al. Informational [Page 42]RFC 6109 Certified Electronic Mail April 2011
4.5.6. LDIFLocationURL Attribute
The 'LDIFLocationURL' attribute contains an [HTTPS] URL that points
to the location of the [LDIF] file defining the provider's record.
When the attribute is present in the record "dn: o=postacert", then
it contains the definition of the entire directory in [LDIF] format.
The LDIF file will have a MIME type of application/pkcs7-mime, with
the parameter smime-type/signed-data. [SMIMEV3] The LDIF file is
encoded using the UTF-8 character set.
Secondary environment records MUST NOT contain the 'LDIFLocationURL'
attribute which is obtained from the main environment's attributes
for all records connected to the provider.
( 1.3.6.1.4.1.16572.2.2.6 NAME 'LDIFLocationURL'
DESC 'URL of the LDIF file that defines the entry'
EQUALITY caseExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
SINGLE-VALUE )
The Directory String ( 1.3.6.1.4.1.1466.115.121.1.15 ) syntax is
defined in [LDAP-SYNTAXES].
4.5.7. providerUnit Attribute
The 'providerUnit' attribute contains the name of secondary operating
environments -- an attribute not present for the main environment.
It is possible for the provider to define several distinct records,
each indicating a single, different, secondary operating environment,
for which it is possible to declare specific attributes that are, if
need be, distinct from those relative to the main and other
environments.
The "DistinguishedName" of the records relative to the secondary
operating environments are of the type
"<providerUnits=<environment>,providerName=<name>,o=postacert>".
Every provider MUST have a record associated to its own main
environment, distinguishable for the absence of the "providerUnit"
attribute within the record and the DistinguishedName.
( 1.3.6.1.4.1.16572.2.2.7 NAME 'providerUnit'
DESC 'Name of the secondary operative environment'
EQUALITY caseIgnoreMatch
SUBSTR caseIgnoreSubstringsMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
SINGLE-VALUE )
Petrucci, et al. Informational [Page 43]RFC 6109 Certified Electronic Mail April 2011
The Directory String ( 1.3.6.1.4.1.1466.115.121.1.15 ) syntax is
defined in [LDAP-SYNTAXES].
4.5.8. LDIFLocationURLObject Object Class
The schema definition of the 'LDIFLocationURLObject' object class:
( 1.3.6.1.4.1.16572.2.1.1 NAME 'LDIFLocationURLObject'
SUP top AUXILIARY
MAY ( LDIFLocationURL ) )
4.5.9. Provider Object Class
The schema definition of the 'provider' object class:
( 1.3.6.1.4.1.16572.2.1.2 NAME 'provider'
SUP top STRUCTURAL
MUST ( providerCertificateHash
providerCertificate
providerName
mailReceipt
managedDomains )
MAY ( description
LDIFLocationURL
providerUnit )
4.5.10. LDIF File Example
The following LDIF file represents an example of a providers'
directory, containing a base root and two fictitious providers. The
inserted certificates are two self-signed certificates used for
example purposes only:
dn: o=postacert
objectclass: top
objectclass: organization
objectClass: LDIFLocationURLObject
o: postacert
LDIFLocationURL: https://igpec.rupa.example.com/igpec.ldif.p7m
description: Base root for the PEC providers directory
dn: providerName=Anonymous Certified Mail S.p.A.,o=postacert
objectclass: top
objectclass: provider
providerName: Anonymous Certified Mail S.p.A.
providerCertificateHash:
7E7AEF1059AE0F454F2643A95F69EC3556009239
providerCertificate;binary::
Petrucci, et al. Informational [Page 44]RFC 6109 Certified Electronic Mail April 2011
MIIDBjCCAm+gAwIBAgIBADANBgkqhkiG9w0BAQQFADBmMQswCQYDVQQGEw
JJVDEpMCcGA1UEChMgQW5vbmltYSBQb3N0YSBDZXJ0aWZpY2F0YSBTLnAu
QS4xLDAqBgkqhkiG9w0BCQEWHXBvc3RhLWNlcnRpZmljYXRhQGFucG9jZX
J0Lml0MB4XDTAyMTIwOTE3MjQxNVoXDTAzMTIwOTE3MjQxNVowZjELMAkG
A1UEBhMCSVQxKTAnBgNVBAoTIEFub25pbWEgUG9zdGEgQ2VydGlmaWNhdG
EgUy5wLkEuMSwwKgYJKoZIhvcNAQkBFh1wb3N0YS1jZXJ0aWZpY2F0YUBh
bnBvY2VydC5pdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAr8J+qK
KdxV9LzDMPqwnEy0P8H/KwbI0Szs8p6UZajZdpeUK0Ncbrv1QyXZNNtSMC
2uL09HDyx8agjgZWdhypnehguiSK3busha15RSpMGhiqxmz2b0HhOG73Gf
alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA
XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
mailReceipt: ssacceptance@postalser.example.com
LDIFLocationURL: https://anpocert.example.com/anpocert.ldif.p7m
managedDomains: mail.anpocert.example.com
managedDomains: cert.company.example.com
managedDomains: costmec.example.com
description: Certified mail services for companies
dn: providerName=Postal Services S.p.A,o=postacert
objectclass: top
objectclass: provider
providerName: Postal Services S.p.A
providerCertificateHash:
e00fdd9d88be0e2cc766b893315caf93d5701a6a
providerCertificate;binary::
MIIDHjCCAoegAwIBAgIBADANBgkqhkiG9w0BAQQFADBuMQswCQYDVQQGEw
JJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIFMuci5sLjEPMA0GA1UE
CxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0YS1jZXJ0aWZpY2F0YU
BzZXJwb3N0YWwuaXQwHhcNMDIxMjA5MTczMjE2WhcNMDMxMjA5MTczMjE2
WjBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIF
Muci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0
YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXQwgZ8wDQYJKoZIhvcNAQEBBQ
ADgY0AMIGJAoGBAKoc7n6zA+sO8NATMcfJ+U2aoDEsrj/cObG3QAN6Sr+l
ygWxYXLBZNfSDWqL1K4edLr4gCZIDFsq0PIEaYZhYRGjhbcuJ9H/ZdtWdX
xcwEWN4mwFzlsASogsh5JeqS8db3A1JWkvhO9EUfaCYk8YMAkXYdCtLD9s
9tCYZeTE2ut9AgMBAAGjgcswgcgwHQYDVR0OBBYEFHPw7VJIoIM3VYhuHa
eAwpPF5leMMIGYBgNVHSMEgZAwgY2AFHPw7VJIoIM3VYhuHaeAwpPF5leM
oXKkcDBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YW
xpIFMuci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5w
b3N0YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXSCAQAwDAYDVR0TBAUwAw
EB/zANBgkqhkiG9w0BAQQFAAOBgQApqeXvmOyEjwhMrXezPAXELMZwv4qq
Petrucci, et al. Informational [Page 45]RFC 6109 Certified Electronic Mail April 2011
r5ri4XuxTq6sS9jRsEbZrS+NmbcJ7S7eFwNQMNxYFVJqdWoLh8qExsTLXn
sKycSnHbCfuphrKvXjQvR2da75U4zGSkroiyvJ2s9TtiCcT3lQtIjmvrFb
aSBiyzj+za7foFUCQmxCLtDaA==
mailReceipt: takecharge@postalser.example.com
LDIFLocationURL: https://postalser.example.com/ldif.txt.p7m
managedDomains: postal-services.example.com
managedDomains: receivedmail.example.com
description: Certified mail services for the public
The following LDIF file represents an example of a PEC providers'
directory, containing a base root and two fictitious providers, the
first of which handles a secondary environment as well. The
certificates inserted are two self-signed certificates used for
example purposes only:
dn: o=postacert
objectclass: top
objectclass: organization
objectClass: LDIFLocationURLObject
o: postacert
LDIFLocationURL: https://igpec.rupa.example.com/igpec.ldif.p7m
description: Base root for the PEC providers directory
dn: providerName=Anonymous Certified Mail S.p.A.,o=postacert
objectclass: top
objectclass: provider
providerName: Anonymous Certified Mail S.p.A.
providerCertificateHash:
7E7AEF1059AE0F454F2643A95F69EC3556009239
providerCertificate;binary::
MIIDBjCCAm+gAwIBAgIBADANBgkqhkiG9w0BAQQFADBmMQswCQYDVQQGEw
JJVDEpMCcGA1UEChMgQW5vbmltYSBQb3N0YSBDZXJ0aWZpY2F0YSBTLnAu
QS4xLDAqBgkqhkiG9w0BCQEWHXBvc3RhLWNlcnRpZmljYXRhQGFucG9jZX
J0Lml0MB4XDTAyMTIwOTE3MjQxNVoXDTAzMTIwOTE3MjQxNVowZjELMAkG
A1UEBhMCSVQxKTAnBgNVBAoTIEFub25pbWEgUG9zdGEgQ2VydGlmaWNhdG
EgUy5wLkEuMSwwKgYJKoZIhvcNAQkBFh1wb3N0YS1jZXJ0aWZpY2F0YUBh
bnBvY2VydC5pdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAr8J+qK
KdxV9LzDMPqwnEy0P8H/KwbI0Szs8p6UZajZdpeUK0Ncbrv1QyXZNNtSMC
2uL09HDyx8agjgZWdhypnehguiSK3busha15RSpMGhiqxmz2b0HhOG73Gf
alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA
XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
Petrucci, et al. Informational [Page 46]RFC 6109 Certified Electronic Mail April 2011
5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
mailReceipt: notifications@anpocert.it.example
LDIFLocationURL: http://anpocert.example.com/anpocert.ldif.p7m
managedDomains: mail.anpocert.example.com
managedDomains: cert.company.example.com
managedDomains: costmec.example.com
description: Certified mail services for companies
dn: providerUnit=Secondary Environment, providerName=Anonymous
Certified Mail S.p.A.,o=postacert
objectclass: top
objectclass: provider
providerName: Certified Mail S.p.A.
providerUnit: Secondary Environment
providerCertificateHash:
7E7AEF1059AE0F454F2643A95F69EC3556009239
providerCertificate;binary::
MIIDBjCCAm+gAwIBAgIBADANBgkqhkiG9w0BAQQFADBmMQswCQYDVQQGEw
JJVDEpMCcGA1UEChMgQW5vbmltYSBQb3N0YSBDZXJ0aWZpY2F0YSBTLnAu
QS4xLDAqBgkqhkiG9w0BCQEWHXBvc3RhLWNlcnRpZmljYXRhQGFucG9jZX
J0Lml0MB4XDTAyMTIwOTE3MjQxNVoXDTAzMTIwOTE3MjQxNVowZjELMAkG
A1UEBhMCSVQxKTAnBgNVBAoTIEFub25pbWEgUG9zdGEgQ2VydGlmaWNhdG
EgUy5wLkEuMSwwKgYJKoZIhvcNAQkBFh1wb3N0YS1jZXJ0aWZpY2F0YUBh
bnBvY2VydC5pdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAr8J+qK
KdxV9LzDMPqwnEy0P8H/KwbI0Szs8p6UZajZdpeUK0Ncbrv1QyXZNNtSMC
2uL09HDyx8agjgZWdhypnehguiSK3busha15RSpMGhiqxmz2b0HhOG73Gf
alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA
XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
mailReceipt: notifications@secondary.anpocert.example.com
managedDomains: management.anpocert.example.com
managedDomains: personnel.anpocert.example.com
description: Corporate internal services
dn: providerName=Postal Services S.r.l.,o=postacert
objectclass: top
objectclass: provider
providerName: Postal Services S.r.l.
providerCertificateHash:
e00fdd9d88be0e2cc766b893315caf93d5701a6a
providerCertificate;binary::
MIIDHjCCAoegAwIBAgIBADANBgkqhkiG9w0BAQQFADBuMQswCQYDVQQGEw
JJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIFMuci5sLjEPMA0GA1UE
CxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0YS1jZXJ0aWZpY2F0YU
Petrucci, et al. Informational [Page 47]RFC 6109 Certified Electronic Mail April 2011
BzZXJwb3N0YWwuaXQwHhcNMDIxMjA5MTczMjE2WhcNMDMxMjA5MTczMjE2
WjBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIF
Muci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0
YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXQwgZ8wDQYJKoZIhvcNAQEBBQ
ADgY0AMIGJAoGBAKoc7n6zA+sO8NATMcfJ+U2aoDEsrj/cObG3QAN6Sr+l
ygWxYXLBZNfSDWqL1K4edLr4gCZIDFsq0PIEaYZhYRGjhbcuJ9H/ZdtWdX
xcwEWN4mwFzlsASogsh5JeqS8db3A1JWkvhO9EUfaCYk8YMAkXYdCtLD9s
9tCYZeTE2ut9AgMBAAGjgcswgcgwHQYDVR0OBBYEFHPw7VJIoIM3VYhuHa
eAwpPF5leMMIGYBgNVHSMEgZAwgY2AFHPw7VJIoIM3VYhuHaeAwpPF5leM
oXKkcDBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YW
xpIFMuci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5w
b3N0YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXSCAQAwDAYDVR0TBAUwAw
EB/zANBgkqhkiG9w0BAQQFAAOBgQApqeXvmOyEjwhMrXezPAXELMZwv4qq
r5ri4XuxTq6sS9jRsEbZrS+NmbcJ7S7eFwNQMNxYFVJqdWoLh8qExsTLXn
sKycPSnHbCfuphrKvXjQvR2da75U4zGSkroiyvJ2s9TtiCcT3lQtIjmvrF
baSBiyzj+za7foFUCQmxCLtDaA==
mailReceipt: ssacceptance@postalser.example.com
LDIFLocationURL: http://postalser.example.com/ldif.txt.p7m
managedDomains: postal-services.example.com
managedDomains: receivedmail.example.com
description: Certified mail services for the public
5. Security-Related Aspects
5.1. Digital Signature
It is recommended that a dedicated hardware module be used to handle
private key and signature operations, the specifications of which are
outside the scope of this document. It's up to the PEC providers to
conform to security requisites expected for the service.
5.2. Authentication
User access to PEC services through the Access Point MUST be allowed
only upon successful user authentication on the system.
For example, authentication might use user-ID and password, or, if
available and considered necessary for the type of service provided,
an electronic ID card or the national services card. Choice of
authentication method is left to the better judgment of the service
provider. Authentication is necessary to guarantee as much as
possible that the message is sent by a PEC user whose identification
data is congruent with the specified sender, so as to avoid
falsification of the latter.
Petrucci, et al. Informational [Page 48]RFC 6109 Certified Electronic Mail April 2011
5.3. Secure Interaction
To guarantee that the original message remains unaltered during
transaction, envelopment and signature are applied on outgoing
messages at the Access Point, and subsequent verification of incoming
messages is done at the Incoming Point.
All communications within the PEC network MUST use secure channels.
Integrity and confidentiality of connections between PEC provider and
user MUST be guaranteed through the use of secure protocols, such as
those based on [TLS] and those that create a secure transport channel
on which non-secure protocols can transmit (e.g., IPsec).
The interaction between providers MUST take place using SMTP on
[TLS], as per [SMTP-TLS]. The Incoming Point MUST provide and
announce its support for the STARTTLS extension, as well as accept
both unencrypted connections (for ordinary mail) and protected ones.
To guarantee complete traceability in the flow of PEC messages, these
MUST NOT transit on systems external to the PEC network. When
exchanging messages between different providers, all transactions
MUST take place between machines that belong to the PEC network or
are directly managed by the provider. An "MX" type record MAY be
associated to each PEC domain defined within the system for name
resolution, in which case secondary reception systems specified in
that record MUST be under direct control of the provider. All in
conformance with [SMTP].
5.4. Virus
Another important security aspect that concerns the PEC system, is
related to the technical and functional architecture that MUST block
the presence of viruses from endangering the security of all handled
messages. It is therefore REQUIRED to have installations and
continuous updates of anti-virus systems that hinder infections as
much as possible without intervening on the content of the certified
mail, in compliance with what has been discussed thus far.
5.5. S/MIME Certificate
In this document the S/MIME certificate profile is defined for use in
the certification of PEC messages done by the providers. The
proposed profile of the S/MIME certificate is based on the IETF
standards [SMIMECERT] and [CRL], which in turn are based on the
standard ISO/IEC 9594-8:2001.
Petrucci, et al. Informational [Page 49]
RFC 6109 Certified Electronic Mail April 2011
5.5.1. Provider-Related Information (Subject)
The information related to the PEC provider holder of the certificate
MUST be inserted in the Subject field (Subject DN). More precisely,
the Subject DN MUST contain the PEC provider's name as it is in the
"providerName" attribute published in the PEC providers directory
(section 4.5), but the Subject DN does not have to match the Provider
entry DN in the LDIF. The providerName MUST be present in the
CommonName or OrganizationName attributes of the "Subject:" field in
the certificate.
Certificates MUST contain an Internet mail address, which MUST have a
value in the subjectAltName extension, and SHOULD NOT be present in
the Subject Distinguished Name.
Valid subjectDN are:
C=IT, O=AcmePEC S.p.A, CN=Posta Certificata
C=IT, O=ServiziPEC S.p.A, CN=Posta Certificata
Valorization of other attributes in the Subject DN, if present, MUST
be done in compliance with [CRL].
5.5.2. Certificate Extensions
Extensions that MUST be present in the S/MIME certificate are:
o Key Usage
o Authority Key Identifier
o Subject Key Identifier
o Subject Alternative Name
The Basic Constraints extension (Object ID:2.5.29.19) MUST NOT be
present.
The valorization of the above listed extensions for the described
profile follows.
The Key Usage extension (Object ID: 2.5.29.15) MUST have the
digitalSignature bit (bit 0) activated and MUST be marked as
critical. The extension MAY contain other active bits corresponding
to different Key Usage, as long as that doesn't contrast with the
indications in [CRL].
Petrucci, et al. Informational [Page 50]RFC 6109 Certified Electronic Mail April 2011
The Authority Key Identifier (Object ID: 2.5.29.35) MUST contain at
least the keyIdentifier field and MUST NOT be marked as critical.
The Subject Key Identifier extension (Object ID: 2.5.29.14) MUST
contain at least the keyIdentifier field and MUST NOT be marked as
critical.
The Subject Alternative Name (Object ID: 2.5.29.17) MUST contain at
least the rfc822Name field and MUST NOT be marked as critical.
Adding other extensions that have not been described in this document
is to be considered OPTIONAL, as long as it remains compliant with
[CRL]; such added extensions MUST NOT be marked as critical.
5.5.3. Example
Following is an example of an S/MIME certificate compliant with the
minimal requisites described in this profile. Values used are of
fictitious providers generated for example purposes only.
5.5.3.1. General-Use Certificate in Annotated Version
An asterisk near the label of an extension means that such an
extension has been marked as critical.
VERSION: 3
SERIAL: 11226 (0x2bda)
INNER SIGNATURE:
ALG. ID: id-sha1-with-rsa-encryption
PARAMETER: 0
ISSUER:
Country Name: IT
Organization Name: Certifier 1
Organizational Unit Name: Certification Service Provider
Common Name: Certifier S.p.A.
VALIDITY:
Not Before: Oct 5, 04 09:04:23 GMT
Not After: Oct 5, 05 09:04:23 GMT
SUBJECT:
Country Name: IT
Organization Name: AcmePEC S.p.A.
Common Name: Certified Mail
PUBLIC KEY: (key size is 1024 bits)
ALGORITHM:
ALG. ID: id-rsa-encryption
PARAMETER: 0
MODULUS: 0x00afbeb4 5563198a aa9bac3f 1b29b5be
7f691945 89d01569 ca0d555b 5c33d7e9
Petrucci, et al. Informational [Page 51]RFC 6109 Certified Electronic Mail April 2011
...
d15ff128 6792def5 b3f884e6 54b326db
cf
EXPONENT: 0x010001
EXTENSIONS:
Subject Alt Name:
RFC Name: posta-certificata@acmepec.it
Key Usage*: Digital Signature
Authority Key Identifier: 0x12345678 aaaaaaaa bbbbbbbb
cccccccc dddddddd
Subject Key Identifier: 0x3afae080 6453527a 3e5709d8 49a941a8
a3a70ae1
SIGNATURE:
ALG. ID: id-sha1-with-rsa-encryption
PARAMETER: 0
VALUE: 0x874b4d25 70a46180 c9770a85 fe7923ce
b22d2955 2f3af207 142b2aba 643aaa61
...
d8fd10b4 c9e00ebc c089f7a3 549a1907
ff885220 ce796328 b0f8ecac 86ffb1cc
5.5.3.2. General-Use Certificate in Dump ASN.1
0 30 794: SEQUENCE {
4 30 514: SEQUENCE {
8 A0 3: [0] {
10 02 1: INTEGER 2
: }
13 02 2: INTEGER 11226
17 30 13: SEQUENCE {
19 06 9: OBJECT IDENTIFIER
: sha1withRSAEncryption (1 2 840 113549 1 1 5)
30 05 0: NULL
: }
32 30 101: SEQUENCE {
34 31 11: SET {
36 30 9: SEQUENCE {
38 06 3: OBJECT IDENTIFIER countryName (2 5 4 6)
43 13 2: PrintableString 'IT'
: }
: }
47 31 28: SET {
49 30 26: SEQUENCE {
51 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10)
56 13 19: PrintableString 'Certificatore 1'
: }
: }
77 31 22: SET {
Petrucci, et al. Informational [Page 52]RFC 6109 Certified Electronic Mail April 2011
79 30 20: SEQUENCE {
81 06 3: OBJECT IDENTIFIER organizationalUnitName (2 5 4 11)
86 13 13: PrintableString 'Certification Service Provider'
: }
: }
101 31 32: SET {
103 30 30: SEQUENCE {
105 06 3: OBJECT IDENTIFIER commonName (2 5 4 3)
110 13 23: PrintableString 'Certificatore S.p.A.'
: }
: }
: }
135 30 30: SEQUENCE {
137 17 13: UTCTime '041005090423Z'
152 17 13: UTCTime '051005090423Z'
: }
167 30 66: SEQUENCE {
169 31 11: SET {
171 30 9: SEQUENCE {
173 06 3: OBJECT IDENTIFIER countryName (2 5 4 6)
178 13 2: PrintableString 'IT'
: }
: }
182 31 23: SET {
184 30 21: SEQUENCE {
186 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10)
191 13 14: PrintableString 'AcmePEC S.p.A.'
: }
: }
207 31 26: SET {
209 30 24: SEQUENCE {
211 06 3: OBJECT IDENTIFIER commonName (2 5 4 3)
216 13 17: PrintableString 'Posta Certificata'
: }
: }
: }
235 30 159: SEQUENCE {
238 30 13: SEQUENCE {
240 06 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549
1 1 1)
251 05 0: NULL
: }
253 03 141: BIT STRING 0 unused bits
: 30 81 89 02 81 81 00 AF BE B4 55 63 19 8A AA 9B
: AC 3F 1B 29 B5 BE 7F 69 19 45 89 D0 15 69 CA 0D
: 55 5B 5C 33 D7 E9 C8 6E FC 14 46 C3 C3 09 47 DD
: CD 10 74 1D 76 4E 71 14 E7 69 42 BE 1C 47 61 85
: 4D 74 76 DD 0B B5 78 4F 1E 84 DD B4 86 7F 96 DF
Petrucci, et al. Informational [Page 53]RFC 6109 Certified Electronic Mail April 2011
: 5E 7B AF 0E CE EA 12 57 0B DF 9B 63 67 4D F9 37
: B7 48 35 27 C2 89 F3 C3 54 66 F7 DA 6C BE 4F 5D
: 85 55 07 A4 97 8C D1 5F F1 28 67 92 DE F5 B3 F8
: [ Another 12 bytes skipped ]
: }
397 A3 123: [3] {
399 30 121: SEQUENCE {
401 30 39: SEQUENCE {
403 06 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17)
408 04 32: OCTET STRING
: 30 1E 81 1C 70 6F 73 74 61 2D 63 65 72 74 69 66
: 69 63 61 74 61 40 61 63 6D 65 70 65 63 2E 69 74
: }
442 30 14: SEQUENCE {
444 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15)
449 01 1: BOOLEAN TRUE
452 04 4: OCTET STRING
: 03 02 07 80
: }
458 30 31: SEQUENCE {
460 06 3: OBJECT IDENTIFIER authorityKeyIdentifier (2 5 29 35)
465 04 24: OCTET STRING
: 30 16 11 11 11 11 AA AA AA AA AA BB BB BB BB CC CC
: CC CC DD DD DD DD
: }
491 30 29: SEQUENCE {
493 06 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14)
498 04 22: OCTET STRING
: 04 14 3A FA E0 80 64 53 52 7A 3E 57 09 D8 49 A9
: 41 A8 A3 A7 0A E1
: }
: }
: }
: }
522 30 13: SEQUENCE {
524 06 9: OBJECT IDENTIFIER
: sha1withRSAEncryption (1 2 840 113549 1 1 5)
535 05 0: NULL
: }
537 03 257: BIT STRING 0 unused bits
: 87 4B 4D 25 70 A4 61 80 C9 77 0A 85 FE 79 23 CE
: B2 2D 29 55 2F 3A F2 07 14 2B 2A BA 64 3A AA 61
: 1F F0 E7 3F C4 E6 13 E2 09 3D F0 E1 83 A0 C0 F2
: C6 71 7F 3A 1C 80 7F 15 B3 D6 1E 22 79 B8 AC 91
: 51 83 F2 3A 84 86 B6 07 2B 22 E8 01 52 2D A4 50
: 9F C6 42 D4 7C 38 B1 DD 88 CD FC E8 C3 12 C3 62
: 64 0F 16 BF 70 15 BC 01 16 78 30 2A DA FA F3 70
: E2 D3 0F 00 B0 FD 92 11 6C 55 45 48 F5 64 ED 98
Petrucci, et al. Informational [Page 54]RFC 6109 Certified Electronic Mail April 2011
: [ Another 128 bytes skipped ]
: }
5.6. PEC Providers Directory
The contents of the PEC providers directory MUST be queried via
[HTTP] on a Secure Socket Layer (SSL), as described in [TLS],
exclusively by licensed providers that have the necessary user
certificates; this access modality guarantees authenticity,
integrity, and confidentiality of data. Each provider downloads the
LDIF file through an [HTTPS] session, which is authenticated by
checking the X.509 certificate issued by a certification authority.
6. PEC System Client Technical and Functional Prerequisites
This section lists the prerequisites that must be respected by a
client in order to guarantee the minimal operative functionalities to
the user of a general PEC system:
o handling of Access and Delivery Points through secure channels;
o handling of user authentication in message dispatch and reception
which make use of standard protocols, such as [IMAP], [POP3], and
[HTTP];
o support for MIME format according to [MIME1] and [MIME5];
o support for "ISO-8859-1 (Latin-1)" character set;
o support for S/MIME v3 standard, as in [SMIMEV3], for verification
of signatures applied to PEC envelopes and notifications.
7. Security Considerations
All security considerations from [CMS] and [SMIMEV3] apply to
applications that use procedures described in this document.
The centralized LDAP server is a critical point for the security of
the whole PEC system. An attack could compromise the whole PEC
system. PEC providers that periodically download the LDIF file
SHOULD use the best security technology to protect it from local
attacks. A PEC provider could be compromised if an attacker changed
a certificate or modified the list of domains associated to it in the
LDIF file that was copied to the PEC provider system.
Petrucci, et al. Informational [Page 55]RFC 6109 Certified Electronic Mail April 2011
When verifying the validity of the signature of a message, the
recipient system SHOULD verify that the certificate included in the
[CMS] message is present in the LDIF file (section 4.5) and that the
domain extracted by the [EMAIL] "From:" header is listed in the
managedDomains attribute associated to said certificate.
8. IANA Considerations
8.1. Registration of PEC Message Header Fields
This document defines new header fields used in the messages that
transit in the PEC network. As specified and required by
[HEADERS-IANA], this document registers new header fields as
Provisional Message Header Fields as follows.
8.1.1. Header Field: X-Riferimento-Message-ID:
Applicable protocol: mail [EMAIL]
Status: provisional
Author/Change controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Specification document: this document, section 2.2.1, Appendix A.
8.1.2. Header Field: X-Ricevuta:
Applicable protocol: mail [EMAIL]
Status: provisional
Author/Change controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Petrucci, et al. Informational [Page 56]RFC 6109 Certified Electronic Mail April 2011
Specification document: this document, sections 2.1.1.1.1, 3.1.2,
3.1.3, 3.1.4, 3.1.6, 3.2.1, 3.2.3, 3.2.4,
3.3.2, 3.3.3, Appendix A.
8.1.3. Header Field: X-VerificaSicurezza:
Applicable protocol: mail [EMAIL]
Status: provisional
Author/Change controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Specification document: this document, sections 2.1.1.1.3, 3.1.3,
3.2.4, Appendix A.
8.1.4. Header Field: X-Trasporto:
Applicable protocol: mail [EMAIL]
Status: provisional
Author/Change controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Specification document: this document, sections 3.1.5, 3.2.2,
Appendix A.
8.1.5. Header Field: X-TipoRicevuta:
Applicable protocol: mail [EMAIL]
Status: provisional
Petrucci, et al. Informational [Page 57]RFC 6109 Certified Electronic Mail April 2011
Author/Change controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Specification document: this document, sections 3.1.5, 3.3.2,
3.3.2.1, 3.3.2.2, 3.3.2.3, Appendix A.
8.1.6. Header Field: X-Mittente:
Applicable protocol: mail [EMAIL]
Status: provisional
Author/Change controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Specification document: this document, sections 3.2.3, Appendix A.
8.2. Registration of LDAP Object Identifier Descriptors
This document defines new LDAP attributes and object classes for
object identifier descriptors. As specified and required by
[LDAP-IANA], this document registers new descriptors as follows per
the Expert Review.
8.2.1. Registration of Object Classes and Attribute Types
Subject: Request for LDAP Descriptor Registration
Descriptor (short name): See comments
Object Identifier: See comments
Person & email address to contact for further information:
See "Author/Change Controller"
Usage: See comments
Petrucci, et al. Informational [Page 58]RFC 6109 Certified Electronic Mail April 2011
Specification: (I-D)
Author/Change Controller:
Claudio Petrucci
DigitPA
Viale Carlo Marx 31/49
00137 Roma
Italy
EMail: PETRUCCI@digitpa.gov.it
Comments:
The following object identifiers and associated object classes/
attribute types are requested to be registered.
OID Descriptor Usage
------------------------ --------------------- ------
1.3.6.1.4.1.16572.2.1.1 LDIFLocationURLObject O
1.3.6.1.4.1.16572.2.1.2 provider O
1.3.6.1.4.1.16572.2.2.1 providerCertificateHash A
1.3.6.1.4.1.16572.2.2.2 providerCertificate A
1.3.6.1.4.1.16572.2.2.3 providerName A
1.3.6.1.4.1.16572.2.2.4 mailReceipt A
1.3.6.1.4.1.16572.2.2.5 managedDomains A
1.3.6.1.4.1.16572.2.2.6 LDIFLocationURL A
1.3.6.1.4.1.16572.2.2.7 providerUnit A
Legend
-------------------
O => Object Class
A => Attribute Type
9. References
9.1. Normative References
[ABNF] Crocker, D., Ed., and P. Overell, "Augmented BNF for
Syntax Specifications: ABNF", STD 68, RFC 5234,
January 2008.
[CMS] Housley, R., "Cryptographic Message Syntax (CMS)",
STD 70, RFC 5652, September 2009.
[CRL] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation
List (CRL) Profile", RFC 5280, May 2008.
Petrucci, et al. Informational [Page 59]RFC 6109 Certified Electronic Mail April 2011
[EMAIL] Resnick, P., Ed., "Internet Message Format", RFC
5322, October 2008.
[HEADERS-IANA] Klyne, G., Nottingham, M., and J. Mogul,
"Registration Procedures for Message Header Fields",
BCP 90, RFC 3864, September 2004.
[HTTP] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee,
"Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616,
June 1999.
[HTTPS] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[IMAP] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL -
VERSION 4rev1", RFC 3501, March 2003.
[LDAP] Zeilenga, K., Ed., "Lightweight Directory Access
Protocol (LDAP): Technical Specification Road Map",
RFC 4510, June 2006.
[LDAP-IANA] Zeilenga, K., "Internet Assigned Numbers Authority
(IANA) Considerations for the Lightweight Directory
Access Protocol (LDAP)", BCP 64, RFC 4520, June 2006.
[LDAP-SYNTAXES] Legg, S., Ed., "Lightweight Directory Access Protocol
(LDAP): Syntaxes and Matching Rules", RFC 4517, June
2006.
[LDIF] Good, G., "The LDAP Data Interchange Format (LDIF) -
Technical Specification", RFC 2849, June 2000.
[MIME1] Freed, N. and N. Borenstein, "Multipurpose Internet
Mail Extensions (MIME) Part One: Format of Internet
Message Bodies", RFC 2045, November 1996.
[MIME5] Freed, N. and N. Borenstein, "Multipurpose Internet
Mail Extensions (MIME) Part Five: Conformance
Criteria and Examples", RFC 2049, November 1996.
[SUBMISSION] Gellens, R. and J. Klensin, "Message Submission for
Mail", RFC 4409, April 2006.
[POP3] Myers, J. and M. Rose, "Post Office Protocol -
Version 3", STD 53, RFC 1939, May 1996.
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[REQ] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[SHA1] Eastlake 3rd, D. and P. Jones, "US Secure Hash
Algorithm 1 (SHA1)", RFC 3174, September 2001.
[MIME-SECURE] Galvin, J., Murphy, S., Crocker, S., and N. Freed,
"Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", RFC 1847, October 1995.
[SMIMEV3] Ramsdell, B. and S. Turner, "Secure/Multipurpose
Internet Mail Extensions (S/MIME) Version 3.2 Message
Specification", RFC 5751, January 2010.
[SMIMECERT] Ramsdell, B. and S. Turner, "Secure/Multipurpose
Internet Mail Extensions (S/MIME) Version 3.2
Certificate Handling", RFC 5750, January 2010.
[SMTP] Klensin, J., "Simple Mail Transfer Protocol", RFC
5321, October 2008.
[SMTP-DSN] Moore, K., "Simple Mail Transfer Protocol (SMTP)
Service Extension for Delivery Status Notifications
(DSNs)", RFC 3461, January 2003.
[SMTP-TLS] Hoffman, P., "SMTP Service Extension for Secure SMTP
over Transport Layer Security", RFC 3207, February
2002.
[TIMESTAMP] Klyne, G. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[TLS] Dierks, T. and E. Rescorla, "The Transport Layer
Security (TLS) Protocol Version 1.2", RFC 5246,
August 2008.
[XML] W3C, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", W3C Recommendation, November 2008,
<http://www.w3.org/TR/2006/REC-xml-20060816/>.
9.2. Informative References
[RFC1034] Mockapetris, P., "Domain names - concepts and
facilities", STD 13, RFC 1034, November 1987.
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[RFC4522] Legg, S., "Lightweight Directory Access Protocol
(LDAP): The Binary Encoding Option", RFC 4522, June
2006.
[RFC4523] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP) Schema Definitions for X.509 Certificates",
RFC 4523, June 2006.
10. Acknowledgments
The Italian document on which this document is based, is a product of
the collaboration of many with the supervision of the National Center
for Informatics in the Public Administration of Italy (DigitPA).
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Appendix A. Italian Fields and Values in English
NOTE: The right column represents a translation of the Italian fields
for readability's sake only. Header fields that MUST be used
are the ones in the left column.
X-Riferimento-Message-ID Reference Message Identifier
X-Ricevuta Notification
non-accettazione non acceptance
accettazione server-user acceptance
preavviso-errore-consegna delivery error advance notice
presa-in-carico server-server acceptance
rilevazione-virus virus detection
errore-consegna delivery error
avvenuta-consegna message delivered
X-Mittente Sender
X-VerificaSicurezza Security Verification
errore error
X-Trasporto Transport
posta-certificata certified mail
errore error
X-TipoRicevuta Notification Type
completa complete
breve brief
sintetica concise
certificatore certificator
Subject values:
Accettazione SERVER-USER ACCEPTANCE
Posta certificata CERTIFIED MAIL
Presa in carico SERVER-SERVER ACCEPTANCE
Consegna DELIVERY
Anomalia messaggio MESSAGE ANOMALY
Problema di sicurezza SECURITY PROBLEM
Avviso di non accettazione NON ACCEPTANCE PEC NOTIFICATION
Avviso di non accettazione VIRUS DETECTION INDUCED NON
per virus ACCEPTANCE PEC NOTIFICATION
Avviso di mancata consegna NON DELIVERY PEC NOTIFICATION
Avviso di mancata consegna NON DELIVERY DUE TO VIRUS PEC
per virus NOTIFICATION
Avviso di mancata consegna NON DELIVERY DUE TO TIMEOUT PEC
per sup. tempo massimo NOTIFICATION
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Italian terms in the DTD relative to the certification XML file:
accettazione server-user acceptance
altro other
avvenuta-consegna delivered
certificato certificate
consegna delivery
data date
dati data
destinatari recipients
esterno external
errore error
errore-consegna delivery error
errore-esteso extensive error
gestore-emittente transmitting provider
giorno day
identificativo identifier
intestazione header
mittente sender
no-dest(inatario) no recipient
no-dominio no domain
non-accettazione non acceptance
nessuno none
oggetto subject
ora hour
posta-certificata certified mail
preavviso-errore-consegna delivery error advance notice
presa-in-carico server-server acceptance
ricevuta notification
ricezione receipt (the act of receiving)
rilevazione-virus virus detection
risposte replies
tipo type
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Authors' Addresses
Claudio Petrucci
DigitPA
Viale Marx 31/49
00137 Roma
Italy
EMail: petrucci@digitpa.gov.it
Francesco Gennai
ISTI-CNR
Via Moruzzi, 1
56126 Pisa
Italy
EMail: francesco.gennai@isti.cnr.it
Alba Shahin
ISTI-CNR
Via Moruzzi, 1
56126 Pisa
Italy
EMail: alba.shahin@isti.cnr.it
Alessandro Vinciarelli
Via delle Vigne di Morena 113
00118 Roma
Italy
EMail: alessandro.vinciarelli@gmail.com
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