Non-interactive Timestamping in the Bounded Storage Model

A timestamping scheme is non-interactive if a stamper can stamp a document without communicating with any other player. The only communication done is at validation time. Non-Interactive timestamping has many advantages, such as information theoretic privacy and enhanced robustness. Non-Interactive timestamping, however, is not possible against polynomial time adversaries that have unbounded storage at their disposal. As a result, no non-interactive timestamping schemes were constructed up to date. In this paper we show non-interactive timestamping is possible in the bounded storage model. I.e., if the adversary has bounded storage, and a long random string is broadcast to all players. To the best of our knowledge, this is the first example of a cryptographic task that is possible in the bounded storage model, but is impossible in the “standard cryptographic setting”, even when assuming “standard” cryptographic assumptions. We give an explicit construction that is secure agai...

• Type: Conference
• Year: 2004
• Where: CRYPTO
• Authors: Tal Moran, Ronen Shaltiel, Amnon Ta-Shma
• Keywords: CRYPTO 2004, Non-interactive Timestamping, Non-interactive Timestamping Schemes, Timestamping Schemes