SesameContract is a conditional decryption service. In order to decrypt a file, the user must satisfy certain conditions that are set at encryption-time. Conditions can range from lock time to passwords to multi-signature verification.

This service is inspired by the Bitcoin transaction contract.

In order to implement conditions such as lock time in a non-distributed environment, a decentralized system of semi-trusted SesameServers is used. A key is split into multiple parts using Shamir's secret sharing algorithm, with each Server holding a fragment. In order to satisfy the condition, a k threshold of those Servers must agree.

Other conditions (password, multi-sig verification) can be implemented in an offline manner, in order to minimize reliance on external servers.

This project is still in a planning stage. Any existing code can only at best be considered a proof of concept.