How to Time-Stamp a Digital Document
- Cite this paper as:
- Haber S., Stornetta W.S. (1991) How to Time-Stamp a Digital Document. In: Menezes A.J., Vanstone S.A. (eds) Advances in Cryptology-CRYPT0’ 90. CRYPTO 1990. Lecture Notes in Computer Science, vol 537. Springer, Berlin, Heidelberg
The prospect of a world in which all text, audio, picture, and video documents are in digital form on easily modifiable media raises the issue of how to certify when a document was created or last changed. The problem is to time-stamp the data, not the medium. We propose computationally practical procedures for digital time-stamping of such documents so that it is infeasible for a user either to back-date or to forward-date his document, even with the collusion of a time-stamping service. Our procedures maintain complete privacy of the documents themselves, and require no record-keeping by the time-stamping service.