A time stamp (or timestamp) demonstrates the existence of a document in a given form at a given (specific) time; it does not deal with when the document was created and who owned the document.
The time stamp's data structure is similar to the structure of certificates. Technically, a time stamp is implemented as just another electronic signature derived from the TSA (Time Stamp Authority).
There is also a so-called qualified time stamp as the equivalent of a qualified electronic seal or qualified electronic signature. Qualified time stamp is created by a qualified time stamp service provider.
The electronically signed structure of a time stamp includes, among many others:
TSA, time stamp authority, proves synchronization of its time source with UTC (Universal Time Coordinated).