Long-Term Archive and Notary Services

Document Charter Long-Term Archive and Notary Services WG (ltans)
Title Long-Term Archive and Notary Services
Last updated 2011-07-19
State Approved
WG State Concluded
IESG Responsible AD Sean Turner
Charter Edit AD (None)
Send notices to (None)


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.