A digital signature scheme based on the discrete logarithm problem, published by Taher ElGamal in 1984. Not to be confused with the ElGamal encryption system.
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Why do we need to hash both the message and the $h$ value in ElGamal signature?
The professor left us a question on ElGamal signatures:
Given the hash function $H$ and message $M$, choose a random $r$ and compute $h=g^r$ and $H(M||h)$. Show that, if $H(M)$ is used instead of ...
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ElGamal signature: Forging a signature of a specific form
I have a question I can't solve from one of the courses I'm currently taking:
Show that given a legitimate ElGamal signature $(S,R)$ on a given message $m$, an attacker
can compute a signature ...
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Elgamal test vectors
I know that Elgamal algorithms have fallen out of fashion, and they are not included in any widespread cryptographic standard nowadays. However, they are still present in several popular crypto ...
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ElGamal Signature Scheme: Recovering the key when reusing randomness
Show how if Alice uses the same value of $k$ to sign two different messages $m_1$ and $m_2$, using the ElGamal signature scheme, Eve can recover the value of $a$ from the corresponding signatures ...
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Safe generator for ElGamal signature
What are the properties a generator $g$ should have to be secure for ElGamal signatures (original scheme)?
I am aware that it is poorly chosen and not secure when $g|p-1$ or $g^{-1}|p-1$, where $p$ ...
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Recovering the key in an ElGamal Signature Scheme variant
From page 318 in Stinson's "Cryptography: Theory and Practice", question 7.3:
Suppose that Alice is using ElGamal Signature Scheme. In order to save time in generating >the random numbers k that ...
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Why is ElGamal considered non-deterministic?
One difference between RSA and ElGamal is that ElGamal isn't necessarily deterministic (while RSA is).
What makes it non-deterministic? Is this advantageous to security? How else does this property ...
