Confirming the existence of given piece of data at a defined point in time (eg. someone invented something before his competitors did). Timestamp token (see above) cryptographically related to the data is attached to it. The result is then digitally signed by a Timestamping authority. Timestamping is governed by RFC3161.

Recording the time of creation or existence of information.

Recording the time when an event happens (typically in a log) or when a piece of information is created or modified.

Message contains a field that tells the age of the information that it carries.