ISO/IEC 18014-1:2008

ISO/IEC 18014 specifies time-stamping techniques. It consists of three parts, which include the general notion, models for a time-stamping service, data structures, and protocols.
ISO/IEC 18014-1:2008 describes a framework and defines the basic notion, the data structures, and protocols which are used  for any time-stamping technique.
ISO/IEC 18014-1:2008:

identifies the objective of a time-stamping authority;
describes a general model on which time-stamping services are based;
describes a process of generating and verifying time-stamp;
defines the data structures of time-stamp token;
defines the basic protocols of time-stamping;
specifies the protocols between the involved entities.