Delay Encryption by Cubing

Abstract

Delay Encryption (often called Timed-Release Encryption) is a scheme in which a message is sent into the future by ensuring its confidentiality only for a given amount of time. We propose a new scheme based on a novel time-lock puzzle. This puzzle relies on the assumption that repeated squaring is an inherently sequential process. We perform an extensive and practical analysis of many classical and quantum attacks on our scheme and conclude that it is secure given some precautions.