ecies-ed25519-morus

Experimental ECIES on Twisted Edwards Curve25519 and MORUS-1280-128

Notes

• Flexible Symmetric Cryptography - Impractical plaintext recovery attack.
• This work misuses the sign & verify keypair in the ed25519 scheme for accomplishing ECIES. We call this, a perversion because we should only use the ephemeral ones (except for the recipient).
• No security audits, and perhaps will not happen.

Example

```rust use randcore::RngCore; use eciesed25519morus::{encryptinto, decrypt_into};

const BUFFERSIZE: usize = 512 * 1024; // avoid higher than this to prevent stackoverflow let mut rng = randcore::OsRng::default(); let senderkeypair = ed25519dalek::SigningKey::generate(&mut rng); let receiverkeypair = ed25519dalek::SigningKey::generate(&mut rng); let senderpublic = senderkeypair.verifyingkey(); let receiverpublic = receiverkeypair.verifyingkey(); let mut randommessage = [0u8; BUFFERSIZE]; let mut decryptedmessage = [0u8; BUFFERSIZE]; let mut ciphertext = [0u8; BUFFERSIZE]; rng.fillbytes(&mut random_message);

let decryptmaterials = encryptinto( &senderkeypair, &receiverpublic, &mut rng, &randommessage[..], &mut ciphertext[..], ) .unwrap(); decryptinto( &receiverkeypair, &senderpublic, &decryptmaterials, &ciphertext[..], &mut decryptedmessage[..], ) .unwrap();

asserteq!(randommessage, decryptedmessage); assertne!(senderpublic, receiverpublic); ```

Features

• no-std environment (for example: wasm):

bash cargo add ecies-ed25519-morus --no-default-features --features="pure"

• std environment (default):

bash cargo add ecies-ed25519-morus

• std and aarch64 environment (for example: Apple Silicon)

bash cargo add ecies-ed25519-morus --features="aarch64-optimizations"

Inspirations

This work is heavily inspired by:

• ecies-ed25519, which uses AES-GCM and ephemeral keypairs (see: notes)
• rust-morus, modified for pure no-std (see: these lines)

Future Works

• [ ] Encrypt & Decrypt with associated data
• [ ] Improve tests with fuzzers & harnesses
• [ ] Add benchmark information
• [ ] Add example and diagrams to elaborate use cases
• [ ] Implement python and c/c++ wrappers