Signatures on Randomizable Ciphertexts

xtended abstract which appears in the 2011 International Conference on Theory and Practice in Public Key Cryptography PKC 2011 (6–9 march 2011, Taormina, Italy) D. Catalano, N. Fazio, R. Gennaro, and A. Nicolosi Eds. Springer-Verlag, LNCS 6571, pages 403–422. Signatures on Randomizable Ciphertexts Olivier Blazy1, Georg Fuchsbauer2, , David Pointcheval1, and Damien Vergnaud1 1 ´Ecole normale sup´erieure - CNRS - INRIA, Paris, France 2 Dept. Computer Science, University of Bristol, UK Randomizable encryption allows anyone to transform a ciphertext into a fresh ciphertext of the same message. Analogously, a randomizable signature can be transformed into a new signature on the same message. We combine randomizable encryption and signatures to a new primitive as follows: given a signature on a ciphertext, anyone, knowing neither the signing key nor the encrypted message, can randomize the ciphertext and adapt the signature to the fresh encryption, thus maintaining public verifiabilit...

• Type: Journal
• Year: 2011
• Where: PKC
• Authors: Olivier Blazy, Georg Fuchsbauer, David Pointcheval, Damien Vergnaud
• Keywords: Computer Science University, Cryptology, Dept Computer Science, PKC 2011, Taormina Italy