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0

Actually, it has not really to do with zero-knowledge. From any public-coin three move identification scheme you can derive a secure signature scheme (in the random oracle model) using what is called the Fiat-Shamir heuristic. Many of these protocols represent honest-verifier zero-knowledge proofs (like the Schnorr, GQ etc. protocols). Now, every such ...

2

Yes, it's okay. This is actually mentioned in passing in the SRP 6 design paper. Previous versions used a random $u$ where an attacker who saw (or could predict) it before revealing $A$ could compute $A = g^a v^{-u}$ and use this to effectively cancel out the long term secret. With $u$ derived from a hash, even if the attacker saw $B$, the dependence of $u$ ...

4

If one-way functions exist, then there is a distribution over graphs (or SAT formulas, or ...) having the property you're asking for. In short, just put the OWF through the Cook-Levin reduction. In a little more detail, Cook-Levin transforms the NP witness-finding question "what is a preimage of $y = f(x)$?" (for random unknown $x$) into the NP ...

4

Even following your edits, there's still some confusion about honest verifier zero knowledge and plain-old (i.e., "possibly malicious verifier") zero knowledge, which is a much stronger property. Your description of HVZK is essentially correct, but with the following clarifications: A 3-move protocol between a prover P and a verifier V for a language ...

1

I've found some lecture notes where, in section 2.4, they give the steps that a simulator would do in order to simulate the view of the honest prover talking to the honest verifier (HVZK). In response to the first question, in the case when the simulator initially guessed wrong the challenge coming from the verifier, the verifier is rewinded but the ...

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But for a split moment, the server knows the secret ... and so is the wireless bug in the cable of the keyboard, the web-cam of your laptop and iPhone, the microwave microphone of the satellite eavesdropping the sound of your keystrokes, etc. If you are afraid of the server don't go in Internet (it is not the server, BTW -it is the screen memory ...

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