ElGamal signature scheme

The ElGamal Signature scheme is a digital signature scheme which is based on the

Correctness

The algorithm is correct in the sense that a signature generated with the signing algorithm will always be accepted by the verifier.

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The signature generation implies

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: H(m) , equiv , x r + s k pmod{p-1}.

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Hence Fermat's little theorem implies

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:

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egin{matrix}

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g^{H(m)} & equiv & g^{xr} g^{ks} \

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& equiv & (g^{x})^r (g^{k})^s \

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& equiv & (y)^r (r)^s pmod p.\

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end{matrix}

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