Abstract—In 1998, Blaze, Bleumer, and Strauss proposed proxy re-signatures, in which a semi-trusted proxy acts as a translator between Alice and Bob to translate a signature from Alice into a signature from Bob on the same message. Following are some open challenges in proxy re-signature schemes: i) the design of multi-use unidirectional systems and ii) determining whether or not a proxy re-signature scheme can be built that translates one type of signature scheme to another. We propose a solution for the first open problem using the property of forward-security. Our forward-secure proxy re-signature scheme which is based on the hardness of factoring translates one person’s signature to another person’s signature and additionally facilitates the signers as well as the proxy to guarantee the security of messages signed in the past even if their secret key is exposed today. To address the second open problem, we construct proxy signature schemes that translates Alice’s Schnorr/ElGamal/RSA signature to Bob’s RSA signature. The Signatures generated by regular signature generation algorithm and the proposed re-signature algorithms are indistinguishable.

Index Terms—Signature translation, Proxy re-signature, Proxy Signature, Proxy revocation, Proxy key

Cite: N. R. Sunitha and B. B. Amberker, "Proxy Re-signature Schemes : Multi-use, Unidirectional & Translations," Journal of Advances in Information Technology, Vol. 2, No. 3, pp. 165-176, August, 2011.doi:10.4304/jait.2.3.165-176