Journal of Cryptology

, Volume 3, Issue 2, pp 99–111

How to time-stamp a digital document

  • Stuart Haber
  • W. Scott Stornetta

DOI: 10.1007/BF00196791

Cite this article as:
Haber, S. & Stornetta, W.S. J. Cryptology (1991) 3: 99. doi:10.1007/BF00196791


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.

Key words


Copyright information

© International Association for Cryptologic Research 1991

Authors and Affiliations

  • Stuart Haber
    • 1
  • W. Scott Stornetta
    • 1
  1. 1.BellcoreMorristownUSA