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Chosen-Ciphertext Secure Proxy Re-Encryption
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Abstract: | In a proxy re-encryption (PRE) scheme, a proxy is given special information that allows it to translate a ciphertext under one key into a ciphertext of the same message under a different key. The proxy cannot, however, learn anything about the messages encrypted under either key. PRE schemes have many practical applications, including distributed storage, email, and DRM. Previously proposed re-encryption schemes achieved only semantic security; in contrast, applications often require security against chosen ciphertext attacks. We propose a definition of security against chosen ciphertext attacks for PRE schemes, and present a scheme that satisfies the definition. Our construction is efficient and based only on the Decisional Bilinear Diffie-Hellman assumption in the standard model. We also formally capture CCA security for PRE schemes via both a game-based definition and simulation-based definitions that guarantee universally composable security. We note that, simultaneously with our work, Green and Ateniese proposed a CCA-secure PRE, discussed herein. |
BibTeX
@misc{eprint-2007-13453, title={Chosen-Ciphertext Secure Proxy Re-Encryption}, booktitle={IACR Eprint archive}, keywords={public-key cryptography / re-encryption, chosen-ciphertext security, obfuscation}, url={http://eprint.iacr.org/2007/171}, note={Full version of paper in ACM CCS 2007. susan@cs.jhu.edu 13815 received 8 May 2007, last revised 29 Oct 2007}, author={Ran Canetti and Susan Hohenberger}, year=2007 }