Cryptology ePrint Archive: Report 2012/665

Uniform Compression Functions Can Fail to Preserve “Full” Entropy

Daniel R. L. Brown

Abstract: To have “full” entropy has been defined in a draft NIST standard to be to have min-entropy very close, proportionally, to the min-entropy of a uniform distribution. A function is uniform if all its preimages have the same size. This report proves that the output of any uniform compression function can fail to have full entropy, even when the input has full entropy.

Category / Keywords: foundations / Entropy, random number generation

Date: received 23 Nov 2012

Contact author: dbrown at certicom com

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Version: 20121128:172004 (All versions of this report)

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