# 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 ...
175 views

### 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 ...
50 views

### 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 ...
116 views

### 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 ...
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 ...
321 views

### 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 ...
2k views

### 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 ...
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 ...
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 ...
120 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 ...
221 views

### 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 ...