ISO/IEC TR 29149:2012 explains how to provide and use time-stamping services so that time-stamp tokens are effective when used to provide timeliness, data integrity, and non-repudiation services in conjunction with other mechanisms. It defines:
how time-stamp requesters should use time-stamp token generation services;
how TSAs (time-stamping authorities) should provide a service of guaranteed quality;
how TSAs should deserve trust based on good practices;
which algorithms and parameters should be used in TST (time-stamp token) generation and TST renewal, so that TSTs resist during the time period during which the TSTs can be verified as being valid;
how time-stamp verifiers should use the time-stamp token verification services, both when validating individual TSTs, and when validating sequences of renewal TSTs.