Cryptology ePrint Archive: Report 2014/281

WCFB: a tweakable wide block cipher

Andrey Jivsov

Abstract: We define a model for applications that process large data sets in a way that enables additional optimizations of encryption operations. We designed a new strong pseudo-random tweakable permutation, WCFB, to take advantage of identified characteristics. WCFB is built with only 2m+1 block cipher invocation for m cipherblocks and approximately 5m XOR operations.

WCFB can benefit from commonly occurring plaintext, such as encryption of a 0^nm sector, and repeated operations on the same wide block.

We prove the birthday-bound security of the mode, expressed in terms of the security of the underlying block cipher.

A case analysis of disk block access requests by Windows 8.1 is provided.

Category / Keywords: secret-key cryptography / wide block encryption mode, PRP, disk encryption, large dataset encryption

Date: received 23 Apr 2014, last revised 16 May 2014

Contact author: crypto at brainhub org

Available format(s): PDF | BibTeX Citation

Version: 20140516:072507 (All versions of this report)

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