Time-lock puzzles

Time-Lock Puzzles in the Random Oracle Model

A time-lock puzzle is a mechanism for sending messages “to the future”. The sender publishes a puzzle whose solution is the message to be sent, thus hiding it until enough time has elapsed for the puzzle to be solved. For timelock puzzles to be useful, generating a puzzle should take less time than solving it. Since adversaries may have access to many more computers than honest solvers, massive...

Time - lock puzzles and timed - release

Pseudonymous Secure Computation from Time-Lock Puzzles

In standard models of secure computation, point-to-point channels between parties are assumed to be authenticated by some pre-existing means. In other cases, even stronger pre-existing setup—e.g., a public-key infrastructure (PKI)—is assumed. These assumptions are too strong for open, peer-to-peer networks, where parties do not necessarily have any prior relationships and can come and go as the...

Time-lock puzzles and timed-release Crypto

Our motivation is the notion of \timed-release crypto," where the goal is to encrypt a message so that it can not be decrypted by anyone, not even the sender, until a pre-determined amount of time has passed. The goal is to \send information into the future." This problem was rst discussed by Timothy May [6]. What are the applications of \timed-release crypto"? Here are a few possibilities (som...

Efficient Modular Exponentiation-Based Puzzles for Denial-of-Service Protection

Client puzzles are moderately-hard cryptographic problems — neither easy nor impossible to solve — that can be used as a countermeasure against denial of service attacks on network protocols. Puzzles based on modular exponentiation are attractive as they provide important properties such as non-parallelisability, deterministic solving time, and linear granularity. We propose an efficient client...