ISO/IEC 18014-2:2009

ISO/IEC 18014-2:2009 presents a general framework for the provision of time-stamping services.
Time-stamping services may generate, renew and verify time-stamp tokens.
Time-stamp tokens are associations between data and points in time, and are created in a way that aims to provide evidence that the data existed at the associated date and time. In addition, the evidence may be used by non-repudiation services.
ISO/IEC 18014-2:2004 specifies mechanisms that generate independent time-stamps: in order to verify an independent time-stamp token, verifiers do not need access to any other time-stamp tokens. That is, time-stamp tokens are not linked, as is the case for the token types defined in ISO/IEC 18014-3.