## Cryptology ePrint Archive: Report 2004/028

Custodian-Hiding Verifiable Encryption

Joseph K. Liu and Victor K. Wei and Duncan S. Wong

Abstract: In a verifiable encryption, an asymmetrically encrypted ciphertext can be publicly verified to be decipherable by a designated receiver while maintaining the semantic security of the message \cite{AsokanShWa98,CamenischDa00,CamenischSh03}. In this paper, we introduce {\em Custodian-Hiding Verifiable Encryption}, where it can be publicly verified that there exists at least one custodian (user), out of a designated group of $n$ custodians (users), who can decrypt the message, while the semantic security of the message and the anonymity of the actual decryptor are maintained. Our scheme is proven secure in the random oracle model. We also introduce two extensions to decryption by a subset of more than one user.

Category / Keywords: Verifiable Encryption, Publicly Verifiable, Anonymity

Publication Info: WISA 2004

Date: received 2 Feb 2004, last revised 22 Aug 2004

Contact author: ksliu9 at ie cuhk edu hk

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | BibTeX Citation

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