Questions tagged [three-pass-protocol]

The three-pass protocol uses commutative encryption to let two people communicate privately without having to exchange keys in advance.

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What would happen if the last message in a three-pass authentication protocol was undelivered?

I did read some articles about the protocol but couldn't figure out what would happen. Would the two parties be unable to verify each other? Or would it be something else? based on the international ...
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1answer
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Multiple encryption using the same key

I am a newbie to this area. I have a program that uses a custom algorithm to encrypt a message. I can encrypt it as many times as I want, but using the same key. I have couple of questions so that I ...
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1answer
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Is it safe to publicly announce the prime number in Shamir three-pass protocol

So say, I want to use a prime number p for anyone that wants to communicate with me using Shamir's Three Pass Protocol. I will be maintaining my secret keypair (encryption exponent, decryption ...
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Would a OTP No-Key Protocol work?

Consider Shamir's No-Key protocol. What if you substitute the asymmetric operations with XOR, each party using an ephemeral OTP. It's symmetric, so you could apply the protocol scheme as if it were ...
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1answer
62 views

With known ciphertext and plaintext, find other party's Three Pass Protocol Key?

If I'm the second party participating in a three pass protocol (for simplicity, let's say Shamir's Three Pass Protocol) such that: Bob sends me a ciphertext I encrypt it and send it back He removes ...
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3 pass protocol

suppose we have 3 matrix named A,B,C (2x2, 3x3, 10x10 or whatever). As we know A^(-1) A C B B^(-1)=C So i take a file and convert it to numbers e.g. ASCII code (lets say 65,72,71...) and i add a ...
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2answers
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2way cryptography

Imagine Alice sending Bob a message. They act like this: Alice encrypts a message with her key and sends it to Bob. Bob encrypts the message again with his key and sends it back to Alice. Alice ...
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1answer
235 views

Does there exist an agreeable algorithm to substitute XOR function in Shamir's no Key Protocol?

I think Shamir's no key protocol (also known as three-pass protocol) is a secure cryptography scheme but the designer only proposed the XOR function to encrypt the message which could be easily broken ...
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209 views

Three-Pass Protocol number theory

I've got a homework problem that I'm having a hard time understanding. It's for the Three-Pass Protocol, and we are given p, the three messages, and are told that the original plain text is one of two ...
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1answer
119 views

Requirements for the modulus in the Massey-Omura three pass protocol

In the Massey-Omura three pass protocol: How many bits long should the prime modulus $M$ be in order to be secure? Should the $M$ be secret? Should the $M$ be generated every time or it could be ...
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Ballot box with multiple parties. All can read it, or none can read it

I am trying to create a decentralized moderation system for the game Diplomacy, a game for seven players. In each round of a face-to-face game, each player writes their moves on paper then puts it in ...
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1answer
499 views

Can two people with different one time pads securely exchange a message like this?

Alice has a message, generates a one time pad, encrypts her message and sends it to Bob. Bob generates his own one time pad, encrypts the message again, and sends it back to Alice. Alice then decrypts ...
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What is the name of this kind of protocol

There is a communication protocol that I believe creates the equivalent of a one time pad, with the downside that the secret message must be transferred multiple times. The protocol is so simple that ...