[cryptography] Proving knowledge of a message with a given SHA-1 without disclosing it?

Francois Grieu fgrieu at gmail.com
Wed Feb 1 07:49:21 EST 2012

On 01/02/2012 13:32, William Whyte wrote :
> You can obviously prove it in the case where Alice claims she knows
> SHA-1(SHA-1(m)), which seems to be the same claim.
Alice discloses h and claims knowledge of m with h=SHA1(m).

That's not equivalent to claiming knowledge of SHA-1(SHA-1(m)),
which anyone can compute as SHA-1(h).

   Francois Grieu

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