Long-Term Archive and Notary Services (ltans)

Last Modified: 2007-10-01

Additional information is available at tools.ietf.org/wg/ltans

Chair(s):

  • Carl Wallace <cwallace@orionsec.com>

  • Tobias Gondrom <tobias.gondrom@gondrom.org>

    Security Area Director(s):

  • Tim Polk <tim.polk@nist.gov>
  • Pasi Eronen <pasi.eronen@nokia.com>

    Security Area Advisor:

  • Tim Polk <tim.polk@nist.gov>

    Mailing Lists:

    General Discussion: ietf-ltans@imc.org
    To Subscribe: ietf-ltans-request@imc.org
    In Body: subscribe
    Archive: http://www.imc.org/ietf-ltans

    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
    period
    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
    expire,
    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
    certificate
    and expiry of trusted time stamp authority certificate. A single
    timestamp is not sufficient for this purpose. Additionally, the
    reliable
    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,
    data
    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
    accordingly.

    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
    example,
    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

    Internet-Drafts:

    Long-term Archive Protocol (LTAP) (126044 bytes)
    Using SCVP to Convey Long-term Evidence Records (30586 bytes)
    Validation and long term verification data for Evidence Records and signed documents (25123 bytes)
    Extensible Markup Language Evidence Record Syntax (59636 bytes)
    Data Structure for Security Suitabilities of Cryptographic Algorithms (DSSC) (61791 bytes)

    Request For Comments:

    Long-Term Archive Service Requirements (RFC 4810) (35690 bytes)
    Evidence Record Syntax (ERS) (RFC 4998) (66888 bytes)
    IETF Secretariat - Please send questions, comments, and/or suggestions to ietf-web@ietf.org.

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