[Cfrg] A note on PRF
Watson Ladd <watsonbladd@gmail.com> Sun, 12 January 2014 14:49 UTC
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From: Watson Ladd <watsonbladd@gmail.com>
To: "cfrg@irtf.org" <cfrg@irtf.org>
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Subject: [Cfrg] A note on PRF
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Let H(k, m) be a PRF with output length n and input all strings. Then I claim that H(H(k, m), "0"), H(H(k,m),"1") is a PRF of output length 2n. A proof of this, together with evaluating the loss of security resulting from such composite, is left as an exercise for the reader. In other words, don't worry about the length of the hash function we adopt for our new Schnorr style signature scheme: it can be extended by classical techniques easily. Sincerely, Watson Ladd
- [Cfrg] A note on PRF Watson Ladd