Curve25519 signatures like in the early Axolotl

Import

rs use ed25519_axolotl::{ random_bytes, str_to_vec32, vec32_to_str, KeyPair };

Generate New Key Pair

```rs // seed: Vec // let keys = KeyPair::new(Some(seed)); let keys = KeyPair::new(None);

println!("{}", keys); ```

Fast Signature

• 64 byte signature
• quick to sign and verify
• don't possible to decode signature back to message ```rs let keys = KeyPair::new(None);

let msg = strtovec32("hello e25519 axolotl".tostring()); let signature = KeyPair::fastsignature( keys.prvk, msg.clone(), Some(random_bytes(64)) );

assert_eq!(KeyPair::verify(keys.pubk, msg, signature), true); println!("ok"); ```

Full Signature

• (64 + message length) byte signature
• slow to sign and verify
• it is possible to decode the signature back to the message ```rs let keys = KeyPair::new(None);

let msg = strtovec32("hello e25519 axolotl".tostring()); let signature = KeyPair::fullsignature( keys.prvk, msg.clone(), Some(random_bytes(64)) );

assert_eq!(KeyPair::verify(keys.pubk, msg, signature), true); println!("ok"); ```

Decode Message

• possible only for full_signature function ```rs let keys = KeyPair::new(None);

let msg = strtovec32("hello e25519 axolotl".tostring()); let mut signmsg = KeyPair::fullsignature( keys.prvk, msg.clone(), Some(randombytes(64)) ); let decodedmsg = KeyPair::decodemessage(keys.pubk, &mut sign_msg);

asserteq!(msg, decodedmsg); println!("ok"); ```

Credits

• Ported to Rust by Miguel Sandro Lucero, miguel.sandro@gmail.com, 2021.09.11.

• You can use it under MIT or CC0 license.

• Curve25519 signatures idea and math by Trevor Perrin, see here

• Derived from axlsign.js written by Dmitry Chestnykh, see here