https://github.com/jedisct1/rust-cpace

A Rust implementation of CPace, a balanced PAKE.
https://github.com/jedisct1/rust-cpace

cpace key-exchange pake rust

Last synced: about 1 month ago
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A Rust implementation of CPace, a balanced PAKE.

• Host: GitHub
• URL: https://github.com/jedisct1/rust-cpace
• Owner: jedisct1
• Created: 2020-05-01T13:41:50.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2023-12-15T21:46:02.000Z (11 months ago)
• Last Synced: 2024-10-05T04:33:27.611Z (about 2 months ago)
• Topics: cpace, key-exchange, pake, rust
• Language: Rust
• Size: 11.7 KB
• Stars: 25
• Watchers: 4
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
[![Documentation](https://docs.rs/pake-cpace/badge.svg)](https://docs.rs/pake-cpace)

# CPace-Ristretto255, a balanced PAKE

A CPace implementation for Rust.

This is a port of the [CPace implementation for libsodium](https://github.com/jedisct1/cpace).

## Blurb

[CPace](https://tools.ietf.org/id/draft-haase-cpace-01.html) is a protocol for two parties that share a low-entropy secret (password) to derive a strong shared key without disclosing the secret to offline dictionary attacks.

CPace is a balanced PAKE, meaning that both parties must know the low-entropy secret.

Applications include pairing IoT and mobile applications using ephemeral pin codes, QR-codes, serial numbers, etc.

## Usage

The CPace protocol requires a single round trip.

It returns a set of two 256-bit (`SHARED_KEY_BYTES` bytes) keys that can be used to communicate in both directions.

```rust

use pake_cpace::CPace;

// client-side

let client = CPace::step1("password", "client", "server", Some("ad")).unwrap();

// server-side

let step2 = CPace::step2(&client.packet(), "password", "client", "server", Some("ad")).unwrap();

// client-side

let shared_keys = client.step3(&step2.packet()).unwrap();

// both parties now have the same set of shared keys

assert_eq!(shared_keys.k1, step2.shared_keys().k1);

assert_eq!(shared_keys.k2, step2.shared_keys().k2);

```

## Notes

- This implementation uses the Ristretto255 group and SHA-512 as the hash function, so it is compatible with the C implementation and can trivially be ported to [wasm-crypto](https://github.com/jedisct1/wasm-crypto).

- Client and server identifiers have a maximum size of 255 bytes.

- `no_std` compatible, WebAssembly compatible.