2.7.8 Long-Term Archive and Notary Services (ltans)

NOTE: This charter is a snapshot of the 78th IETF Meeting in Maastricht, Netherlands. It may now be out-of-date.

Last Modified: 2009-09-24


Carl Wallace <cwallace@cygnacom.com>
Tobias Gondrom <tobias.gondrom@gondrom.org>

Security Area Director(s):

Sean Turner <turners@ieca.com>
Tim Polk <tim.polk@nist.gov>

Security Area Advisor:

Tim Polk <tim.polk@nist.gov>

Mailing Lists:

General Discussion: ltans@ietf.org
To Subscribe: http://www.ietf.org/mailman/listinfo/ltans
In Body: subscribe
Archive: http://www.ietf.org/mail-archive/web/ltans/current/maillist.html

Description of Working Group:

In many scenarios, users need to be able to ensure and prove the
existence and validity of data, especially digitally signed data, in a
common and reproducible way over a long and possibly undetermined
of time.

Cryptographic means are useful, but they do not provide the whole
solution. For example, digital signatures (generated with a particular
key size) might become weak over time due to improved computational
capabilities, new cryptanalytic attacks might "break" a digital
signature algorithm, public key certificates might be revoked or
and so on.

Complementary methods covering potential weaknesses are necessary.

Long-term non-repudiation of digitally signed data is an important
aspect of PKI-related standards. Standard mechanisms are needed to
handle routine events, such as expiry of signer's public key
and expiry of trusted time stamp authority certificate. A single
timestamp is not sufficient for this purpose. Additionally, the
preservation of content across change of formats, application of
electronic notarizations, and subsequent notary services require
standard solutions.

The objective of the LTANS working group is to define requirements,
structures and protocols for the secure usage of the necessary archive
and notary services. First, the requirements for the long-term archive
will be collected. Based on that information we will develop a protocol
to access archive services supplying long-term non-repudiation for
signed documents and define common data structures and formats. Upon
completion of the archive-related specifications, we will address
'notary services' in a similar way. The term 'notary services' is not
clearly defined. The working group will determine which functions need
standards, including transformation of documents from one format to
another without losing the value of evidence, electronic notarization,
and further verification of legal validity of signed documents. We will
determine the needs via the requirements paper and act upon the results

Work done by the IETF Working Groups PKIX, S/MIME and XMLDSIG will be
used as the basis to define those structures and protocols. For
the Internet-Drafts "Archive Time-Stamps Syntax (ATS)" and "Trusted
Archive Protocol (TAP)" and RFC 3029, "Data Validation and Certificate
Server Protocols (DVCS)", contain applicable concepts.

Goals and Milestones:

Done  Initial requirements for long-term archive I-D
Done  Initial data structures for long-term archive I-D
Done  Revised requirements for long-term archive I-D
Done  Revised data structures for long-term archive I-D
Done  Initial requirements for notary services I-D
Done  Initial protocol for long-term archive I-D
Done  Revised requirements for notary services I-D
Done  WG Last call requirements for long-term archive I-D
Done  Submit requirements for long-term archive to IESG as informational
Done  Submit data structures for long-term archive to IESG as proposed standard
Done  WG Last call data structures for long-term archive I-D
Nov 2007  Protocol revisions for long-term archive I-D
Feb 2008  WG Last call protocol for long-term archive I-D
Mar 2008  Submit protocol for long-term archive to IESG as proposed standard
May 2008  Recharter or close the working group


  • draft-ietf-ltans-validate-03.txt
  • draft-ietf-ltans-ari-01.txt
  • draft-ietf-ltans-xmlers-08.txt

    Request For Comments:

    RFC4810 I Long-Term Archive Service Requirements
    RFC4998 PS Evidence Record Syntax (ERS)
    RFC5276 PS Using the Server-Based Certificate Validation Protocol (SCVP) to Convey Long-Term Evidence Records
    RFC5698 PS Data Structure for the Security Suitability of Cryptographic Algorithms (DSSC)

    Meeting Minutes