MAC http://tau-foc-f19.wikidot.com/forum/t-12997569/mac Posts in the discussion thread "MAC" Tue, 18 Aug 2026 04:41:49 +0000 http://tau-foc-f19.wikidot.com/forum/t-12997569#post-4485208 (no title) http://tau-foc-f19.wikidot.com/forum/t-12997569/mac#post-4485208 Fri, 31 Jan 2020 16:46:39 +0000 nbitansky 1746223 MACs are indeed not guaranteed to be pseudorandom.

]]> http://tau-foc-f19.wikidot.com/forum/t-12997569#post-4484722 (no title) http://tau-foc-f19.wikidot.com/forum/t-12997569/mac#post-4484722 Fri, 31 Jan 2020 08:42:35 +0000 Amit I thought of the following counter example, LMK if it works:
You can add 0 in the beginning of every signature of a valid MAC. I guess it will not harm the unforgeability, but it will definitely be distinguishable.

]]> http://tau-foc-f19.wikidot.com/forum/t-12997569#post-4484715 MAC http://tau-foc-f19.wikidot.com/forum/t-12997569/mac#post-4484715 Fri, 31 Jan 2020 08:26:28 +0000 Amit If we have a MAC with authorization algorithm AUTH, does the following must be computationally indistinguishable?
1. U_n, Auth_sk(U_n)
2. U_n, (U_n)^'

Basically the question is does the fact that the adversary cannot forge a signature to a new message means that he cannot tell when the signature is correct?
Thanks!

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