**Construction of UOWHF: Tree Hashing Revisited**

*Palash Sarkar*

**Abstract: **We present a binary tree based parallel algorithm for extending the domain of a UOWHF.
The key length expansion is $2m$ bits for $t=2$; $m(t+1)$ bits for $3\leq t\leq 6$ and
$m\times(t+\lfloor\log_2 (t-1)\rfloor)$ bits for $t\geq 7$, where $m$ is the length
of the message digest and $t\geq 2$ is the height of the binary tree.

**Category / Keywords: **UOWHF, hash function, binary tree

**Date: **received 12 May 2002, last revised 16 Feb 2004

**Contact author: **palash at isical ac in

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

**Note: **The revision removes some minor but potentially confusing typos.

**Version: **20040216:085103 (All versions of this report)

**Short URL: **ia.cr/2002/058

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