Introduction to "Timestamping service". Fields of use.

"Timestamping service" is analogous to a notary public. Client provides data to the service, service marks it with actual timestamp, and signs with a digital signature.

Client data + actual time + digsig = timestamp

Timestamp is a digitally signed certificate of an actual time value and a client's data. Such certificate provides a way to verify existence of a given data at a witnessed time.

“Timestamps” form a chain, in which each a subsequent “timestamp” contains proof, that given out exactly after previous (hash of previous joins in a “timestamp”). Thus, the risk of falsification of “timestamp” goes down — if service will give out the “timestamp” backdated, it can be detect.
Uses of fastening allows you to control service.

Chain of “timestamp” is a sequence of «marks of time», where each the subsequent «mark of time» has proof, that was given out exactly after previous.

Purviews service

Purviews such service there can be a great number. Here some examples.

•  The author of original idea (program, image, draft, etc.) wants to have proof that possessed this idea before other.
• “Timestamp” can specify on that, when a man confirmed a document with signature or what moment he wants from, that a signature entered into legal force. That can be utillized for the electronic conduct of business.
• Important documents, expandable on a network, for example reports on sites, can be notarized with “timestamp”. Then the simple delete of information will not result in elimination of proofs, that they were published in set time.
• Service can partly decide a problem, all of the systems with assimetrichnoy cryptography, described one of authors of PGP.

Phil Zimmermann:
“Nothing will stop an unconscientious user from the «translation of pointers» of his system clock for the generation of certificates of the opened keys and digital signatures which will seem created in other, than in actual fact, time. He can do so that the signed information seemed signed sooner or later, what was in reality, or that his key pair was created in the past or in the future. It can bring him some legal or financial benefit, for example, creating a certain loop-hole, allowing to renounce from an own signature.”

If it will be beforehand stipulated among users, that the date of cancellation must be notarized by «timestamp» – to conduct such machination will be difficult.