## CryptoDB

### Paper: Scalable, Server-Passive, User-Anonymous Timed Release Public Key Encryption from Bilinear Pairing

Authors: Ian F. Blake Aldar C-F. Chan URL: http://eprint.iacr.org/2004/211 Search ePrint Search Google We consider the problem of sending messages into the future, commonly known as timed release cryptography. Existing schemes for this task either solve the relative time problem with uncontrollable, coarse-grained release time (time-lock puzzle approach) or do not provide anonymity to sender and/or receiver and are not scalable (server-based approach). Using a bilinear paring on any Gap Diffie-Hellman group, we solve this problem by giving a scalable, server-passive and user-anonymous timed release public-key encryption scheme which allows precise absolute release time specifications. Unlike the existing server-based schemes, the trusted time server in our scheme is completely passive --- no interaction between it and the sender or receiver is needed; it is even not aware of the existence of a user, thus assuring the anonymity of both the sender and receiver of a message and the privacy of the message. Besides, our scheme also has a number of desirable properties including self-authenticated time-bound key updates, a single form of update for all receivers, simple public-key renewal and key insulation, making it a scalable and appealing solution.
##### BibTeX
@misc{eprint-2004-12183,
title={Scalable, Server-Passive, User-Anonymous Timed Release Public Key Encryption from Bilinear Pairing},
booktitle={IACR Eprint archive},
keywords={timed release encryption, bilinear pairing, identity-based encryption, anonymity},
url={http://eprint.iacr.org/2004/211},
note={- aldar@comm.utoronto.ca 12670 received 25 Aug 2004, last revised 9 Sep 2004},
author={Ian F. Blake and Aldar C-F. Chan},
year=2004
}