Verifiable Delay Function (VDF)
cryptography · consensus
A function designed to require a minimum sequential computation time while producing a proof that is quick to verify.
A verifiable delay function (VDF) is designed around a computation believed to require a prescribed number of sequential steps, even with substantial parallel hardware. It produces an output and a proof that other participants can verify much faster than they can reproduce the delay.
The delay depends on the construction's cryptographic assumptions, parameters, and the fastest available specialized implementation. A VDF does not measure wall-clock time perfectly across every device and needs an agreed input source to prevent participants from choosing favorable starting values.
VDFs are studied for randomness, leader election, and time-delay mechanisms. They differ from proof of work because the goal is a predictable delay, not an open-ended race to find a hash below a target.
Related terms
Verifiable Random Function (VRF)
→A cryptographic function that produces random-looking output with a proof anyone can verify using a public key.
cryptography · consensus
Timelock
→A spending rule that prevents a transaction or output from being used until a specified time or block height.
scripting · bitcoin
Proof of Work (PoW)
→A consensus mechanism that makes block production require verifiable computational work.
mining · blockchain · consensus