Cryptology ePrint Archive: Report 2017/498

Full-State Keyed Duplex With Built-In Multi-User Support

Joan Daemen and Bart Mennink and Gilles Van Assche

Abstract: The keyed duplex construction was introduced by Bertoni et al.(SAC 2011) and recently generalized to full-state absorption by Mennink et al.(ASIACRYPT 2015). We present a generalization of the full-state keyed duplex that natively supports multiple instances by design, and perform a security analysis that improves over that of Mennink et al. in terms of a more modular security analysis and a stronger and more adaptive security bound. Via the introduction of an additional parameter to the analysis, our bound demonstrates a significant security improvement in case of nonce-respecting adversaries. Furthermore, by supporting multiple instances by design, instead of adapting the security model to it, we manage to derive a security bound that is largely independent of the number of instances.

Category / Keywords: secret-key cryptography / Duplex construction, full-state, distinguishing bounds, authenticated encryption

Original Publication (with minor differences): IACR-ASIACRYPT-2017

Date: received 31 May 2017, last revised 1 Sep 2017

Contact author: joan at cs ru nl

Available format(s): PDF | BibTeX Citation

Note: Version after processing Asiacrypt reviews

Version: 20170901:091150 (All versions of this report)

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