rust

samp

Rust implementation of SAMP (Substrate Account Messaging Protocol).

Install

[dependencies]
samp-core = "1.1"

Usage

use samp::encryption::{compute_view_tag, decrypt, encrypt, sr25519_signing_scalar};
use samp::secret::Seed;
use samp::types::{ContentType, Nonce, Plaintext, Pubkey};
use samp::wire::{decode_remark, encode_encrypted, encode_public, Remark};

let sender_seed = Seed::from_bytes([0u8; 32]); // your sr25519 seed
let recipient_pub = Pubkey::from_bytes([0u8; 32]); // recipient's sr25519 public key

// Public message
let remark = encode_public(&recipient_pub, "Hello from Rust");

// Encrypted message
let nonce = Nonce::from_bytes([0u8; 12]); // use a random 12-byte IV
let plaintext = Plaintext::from_bytes(b"Private message".to_vec());
let ciphertext = encrypt(&plaintext, &recipient_pub, &nonce, &sender_seed).unwrap();
let tag = compute_view_tag(&sender_seed, &recipient_pub, &nonce).unwrap();
let enc_remark = encode_encrypted(ContentType::Encrypted, tag, &nonce, &ciphertext);

// Decrypt
let recipient_seed = Seed::from_bytes([0u8; 32]);
let scalar = sr25519_signing_scalar(&recipient_seed);
let Remark::Encrypted { nonce: n, ciphertext: ct, .. } = decode_remark(&enc_remark).unwrap() else {
    panic!("expected Encrypted");
};
let plaintext = decrypt(&ct, &n, &scalar).unwrap();

API

Wire

Function	Description
encode_public	Public message (0x10)
encode_encrypted	Encrypted or thread message (0x11/0x12)
encode_channel_create	Channel creation (0x13)
encode_channel_msg	Channel message (0x14)
encode_group	Group message (0x15)
decode_remark	Parse any SAMP remark
encode_thread_content / decode_thread_content	Thread plaintext (refs + body)
encode_channel_content / decode_channel_content	Channel plaintext (refs + body)
decode_group_content	Group plaintext (refs + body)
encode_group_members / decode_group_members	Group member list
channel_ref_from_recipient	Extract channel BlockRef from recipient field

Crypto

Function	Description
encrypt / decrypt	1:1 ECDH + ChaCha20-Poly1305
decrypt_as_sender	Sender self-decryption via sealed_to
encrypt_for_group / decrypt_from_group	Multi-recipient encryption
sr25519_signing_scalar	Derive Ristretto255 scalar from sr25519 seed
public_from_seed	Derive public key from seed
compute_view_tag / check_view_tag	1-byte recipient filter
unseal_recipient	Recover recipient from sealed_to field
build_capsules / scan_capsules	Group capsule construction and scanning

Types

BlockRef, Remark, ContentType, SampError, GroupEncrypted

Test

cargo test

248 tests: conformance, round-trip, property-based (proptest), scale, metadata, extrinsic. 97%+ line coverage.