Cryptology ePrint Archive: Report 2013/835

A Modular Framework for Building Variable-Input Length Tweakable Ciphers

Thomas Shrimpton and R. Seth Terashima

Abstract: We present the Protected-IV construction (PIV) a simple, modular method for building variable-input-length tweakable ciphers. At our level of abstraction, many interesting design opportunities surface. For example, an obvious pathway to building beyond birthday-bound secure tweakable ciphers with performance competitive with existing birthday-bound-limited constructions. As part of our design space exploration, we give two fully instantiated PIV constructions, TCT1 and TCT2; the latter is fast and has beyond birthday-bound security, the former is faster and has birthday-bound security. Finally, we consider a generic method for turning a VIL tweakable cipher (like PIV) into an authenticated encryption scheme that admits associated data, can withstand nonce-misuse, and allows for multiple decryption error messages. Thus, the method offers robustness even in the face of certain sidechannels, and common implementation mistakes.

Category / Keywords: secret-key cryptography / tweakable block ciphers, authenticated encryption, disk encryption, nonce misuse

Original Publication (with major differences): IACR-ASIACRYPT-2013

Date: received 9 Dec 2013, last revised 22 Aug 2014

Contact author: seth at cs pdx edu

Available format(s): PDF | BibTeX Citation

Note: Typo fixes and minor clarifications.

Version: 20140822:184230 (All versions of this report)

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