# Questions tagged [commutative-encryption]

A commutative encryption system allows a message encrypted with two different keys to be decrypted using the keys in either order.

32 questions
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### are commutative digital signature possible

Say we have a message $m$. Signer 1 will sign this message using his digital signature to produce $\operatorname{Sign}_1(m)$. Now, say another signer 2 wants to sign the output of the previous ...
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### Can multiplication of two primes be seen as a strong cipher?

If we were define such a cipher: A reversible function that would accept a message $M$ and an initialization vector $\text{IV}_1$ $\operatorname{map}(\text{IV}_1, M)$ which can map an input $M$ to a ...
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### Are there transitive ciphers (either symmetric and asymmetric)

Say Alice has information that's already encrypted with Bob's key. She wants Bob to decrypt it without knowing what he just decrypted. So she encrypts it with her key and sends it to him, he decrypts ...
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### Is there a mental poker algorithm that does not rely on commutative encryption?

The algorithm for mental poker that I saw on Wikipedia and everywhere else relies on an encryption algorithm such that $E_k(E_j(P)) = E_j(E_k(P))$, but I can't find a modern and secure algorithm for ...
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### Crypto libary with Commutative Encryption

I want to implement Mental Poker in JavaScript as a toy program and lead in to a larger serious project so I did my research and found Massey-Omura cryptosystem and the Shamir three-pass protocol ...
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### Decrypting an encrypted text out of order

Does there exist a cipher that can be encrypted twice with two different keys and then decrypted twice using either key first? For example: ...
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### Commutative Encryption with RSA scheme?

I wanted to know how I could manage to do what I'm going to tell you next, with the RSA encryption/decryption scheme. So Alice and Bob each have a public key $(n, e)$ and a private key $(p, q, d)$; ...
355 views