Low-cost Anonymous Timed-Release Encryption

We propose a new server-based efficient protocol for time-release encryption (TRE), or - as sometimes referred to - sending information "into the future". As with other recently-proposed schemes, ours is based on the use of bilinear pairings on any Gap Diffie-Hellman group, allowing absolute release time of the encrypted data. Our protocol possesses the required properties regarding user anonymity and server passivity. It also provides almost-costless scalability in settings with multiple time-servers, and improves significantly upon existing TRE schemes, in terms of computational and communication cost. This makes our approach well-suited to a number of emerging e-applications that require future decryption of confidential data.