Dealerless Multi-Server Timed-Release Encryption Scheme with Privacy-Preserving Encoding
Shao-Heng Chen, Fu-Kuo Tseng, Rong-Jaye Chen · International Conference on Information Security · 2015
The idea of “sending messages into the future” was first introduced in 1993 and brought up a new research track of timed-release encryption (TRE) scheme. However, most TRE schemes are constructed with a centralized and fullytrusted time server. This server should periodically generate and broadcast time-bound keys for legitimate users. Therefore, this setting is not scalable and suffers from single point failure. In addition, all of the time-bound keys are required to be stored at the server for all the possible time instances. In this paper, we proposed a timed-release encryption scheme with an efficient and privacy-preserving encoding in a decentralized/dealerless setting from the ciphertext-policy attribute-based encryption (CP-ABE) scheme. Our improved TRE scheme can be applied in the services where only semi-trusted servers are available.