Questions tagged [hashed-elgamal]
The hashed-elgamal tag has no usage guidance.
7 questions
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Why $1\leq r\leq p-1$ verification is needed for (hashed) Elgamal signature?
I am reading the "Handbook of Applied Cryptography" by Menezes et al. (hashed) ElGamal Signature verification in this book talks about verification of $1\leq r\leq p-1$. Subsequently, this ...
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Source of encryption scheme used in blockchain based IoT
I've found the following encryption scheme
UserA: $$sk_A, pk_A = sk_A \cdot G$$
UserB: $$sk_B, pk_B = sk_B \cdot G$$
Enc: UserA
$$u \in \mathbb{Z}_q^* \\
Y = u \cdot pk_B \\
S = H(U) \oplus m \\
C = (...
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Using GP/PARI how would you solve this randomised Elgamal question?
I know how to solve this question manually, but I don't know how to solve it using the program gp/pari. It is based on randomised Elgamal
Let p = 739. Given the following ciphertext of some message m1 ...
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Why Bellare-Micali Oblivious Transfer Construction requires ElGamal with hashed key?
The idea of the Bellare-Micali Oblivious Transfer Constructions is the following:
Informally, the receiver is required to generate two public keys $y_b$, $y_{b-1}$ such that it knows only the secret ...
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Understanding ElGamal encryption for a Mental Poker Case
I am looking to understand ElGamal encryption as it is used in a specic context described below. I am interested in creating a practical form of Mental Poker for games other than poker developed by ...
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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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Malleability of ElGamal and Hashed ElGamal
Question: Suppose A encrypts a number $x$ which indicates her bid on a contract, using ElGamal encryption. Say that the encryption of $x$ produces a ciphertext $c$. Explain how E can modify $c$ to ...
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