Cryptology ePrint Archive: Report 2007/190

Some General Results on Chosen-ciphertext Anonymity in Public-key Encryption

Tian Yuan

Abstract: In applications of public-key encryption schemes, anonymity(key-privacy) as well as security(data-privacy) is useful and widely desired. In this paper some new and general concepts in public-key encryption, i.e., “master-key anonymity”, “relevant master-key anonymity” and “key-integrity”, are introduced(the former two are defined for IBE schemes and the latter one is for any public-key encryption scheme). By the concept of master-key anonymity, we prove that chosen-plaintext master-key anonymity is a sufficient condition for chosen-ciphertext anonymity in the recent elegant Canetti-Halevi-Katz and Boneh-Katz construction. By the concept of key-integrity, we prove it is(together with chosen-plaintext anonymity)a sufficient/necessary condition for chosen-ciphertext anonymity. In addition to these general consequences, some practical examples are also investigated to show such concepts’ easy-to-use in practice.

Category / Keywords: public-key cryptography / Anonymity; Key-privacy; Master-Key Anonymity; Key-integrity

Date: received 20 May 2007

Contact author: tianyuan_ca at sina com

Available format(s): PDF | BibTeX Citation

Version: 20070522:202631 (All versions of this report)

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