Non-interactive Timestamping in the Bounded Storage Model

Abstract

Abstract.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. Unfortunately, no such scheme exists against polynomial time adversaries that have unbounded storage at their disposal. In this paper we show non-interactive timestamping is possible in the bounded storage model. In this model it is assumed that all parties participating in the protocol have small storage, and that in the beginning of the protocol a very long random string (which is too long to be stored by the players) is transmitted. 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 assuming cryptographic assumptions. We give an explicit construction that is secure against all bounded storage adversaries, and a significantly more efficient construction secure against all bounded storage adversaries that run in polynomial time.

One‐round provably secure yoking‐proof for RFID applications

“…Therefore, the above attack is unavoidable in such kind of yoking‐proof schemes. We now state the following theorems about the security and privacy of the proposed scheme.Theorem Let t 1 and t 2 be the secure timestamps and PRF be the secure pseudorandom function . The yoking‐proof scheme Π in Section 3.1 is secure under Definition .…”

“…The yoking‐proof scheme Π in Section 3.1 is secure under Definition . The proof is given in Appendix .Theorem Let t 1 and t 2 be the secure timestamps and PRF be the secure pseudorandom function . The yoking‐proof scheme Π in Section 3.1 is private under Definition .…”

Non-interactive Cryptographic Timestamping Based on Verifiable Delay Functions

“…In the classical literature, almost every timestamping service requires interaction with a group of validators and provides security guarantees only for relative timestamping. Non-interactive timestamping has been explored before in [MSTS04], where the authors present a generic impossibility result, as an adversarial prover would simply need to simulate the execution of an honest prover to generate a fake timestamp. They sidestep this result by working in the bounded-storage model where they construct a secure protocol.…”

Cryptography in the bounded quantum-storage model

“…Such a scheme clearly does not exist without a bound on the committer's memory, even under computational assumptions and using quantum communication: a corrupt committer could always store (possibly quantumly) all the information sent, until opening time, and only then follow the honest committer's algorithm to figure out what should be sent to convincingly open a 0 or a 1. Note that in the classical bounded-storage model, it is known how to do time-stamping that is noninteractive in our sense: a player can time-stamp a document while only receiving information [14]. However, no reasonable BC protocol that time-stamps a bit exist in this model.…”