use crate::P256KeyMaterial; use anyhow::{anyhow, ensure, Result}; use p256::ecdsa::signature::{Signer, Verifier}; use std::str::FromStr; use ucan::builder::UcanBuilder; // Need to: // // - generate new random keypair // - generate keypair from seed // - read/write secret keypair (eg, for PDS config loading) // - sign bytes (and ipld?) using keypair // - verify signature bytes (and ipld?) using pubkey const MULTICODE_P256_BYTES: [u8; 2] = [0x80, 0x24]; const MULTICODE_K256_BYTES: [u8; 2] = [0xe7, 0x01]; #[derive(Clone, PartialEq, Eq)] pub struct KeyPair { public: p256::ecdsa::VerifyingKey, secret: p256::ecdsa::SigningKey, } #[derive(Clone, PartialEq, Eq)] pub enum PubKey { P256(p256::ecdsa::VerifyingKey), K256(k256::ecdsa::VerifyingKey), } impl KeyPair { pub fn new_random() -> Self { let signing = p256::ecdsa::SigningKey::random(&mut p256::elliptic_curve::rand_core::OsRng); KeyPair { public: signing.verifying_key(), secret: signing, } } pub fn from_bytes(bytes: &[u8]) -> Result { let signing = p256::ecdsa::SigningKey::from_bytes(bytes)?; Ok(KeyPair { public: signing.verifying_key(), secret: signing, }) } pub fn to_bytes(&self) -> Vec { self.secret.to_bytes().to_vec() } pub fn pubkey(&self) -> PubKey { PubKey::P256(self.public) } pub fn sign_bytes(&self, data: &[u8]) -> String { let sig = self.secret.sign(data); data_encoding::BASE64URL_NOPAD.encode(&sig.to_vec()) } fn ucan_keymaterial(&self) -> P256KeyMaterial { P256KeyMaterial(self.public, Some(self.secret.clone())) } /// This is currently just an un-validated token; we don't actually verify these. pub fn ucan(&self, did: &str) -> Result { let key_material = self.ucan_keymaterial(); let rt = tokio::runtime::Builder::new_current_thread() .enable_all() .build()?; rt.block_on(build_ucan(key_material, did)) } pub fn to_hex(&self) -> String { data_encoding::HEXUPPER.encode(&self.to_bytes()) } pub fn from_hex(hex: &str) -> Result { Ok(Self::from_bytes( &data_encoding::HEXUPPER.decode(hex.as_bytes())?, )?) } } async fn build_ucan(key_material: P256KeyMaterial, did: &str) -> Result { let token_string = UcanBuilder::default() .issued_by(&key_material) .for_audience(did) .with_nonce() .with_lifetime(60 * 60 * 24 * 90) .build()? .sign() .await? .encode()?; Ok(token_string) } impl PubKey { pub fn verify_bytes(&self, data: &[u8], sig: &str) -> Result<()> { let sig_bytes = data_encoding::BASE64URL_NOPAD.decode(sig.as_bytes())?; // TODO: better way other than this re-encoding? let sig_hex = data_encoding::HEXUPPER.encode(&sig_bytes); match self { PubKey::P256(key) => { let sig = p256::ecdsa::Signature::from_str(&sig_hex)?; Ok(key.verify(data, &sig)?) } PubKey::K256(key) => { let sig = k256::ecdsa::Signature::from_str(&sig_hex)?; Ok(key.verify(data, &sig)?) } } } pub fn key_type(&self) -> String { match self { PubKey::P256(_) => "EcdsaSecp256r1VerificationKey2019", PubKey::K256(_) => "EcdsaSecp256k1VerificationKey2019", } .to_string() } /// This public verification key encoded as base58btc multibase string pub fn to_multibase(&self) -> String { let mut bytes: Vec = vec![]; match self { PubKey::P256(key) => { bytes.extend_from_slice(&MULTICODE_P256_BYTES); bytes.extend_from_slice(&key.to_encoded_point(true).to_bytes()); } PubKey::K256(key) => { bytes.extend_from_slice(&MULTICODE_K256_BYTES); bytes.extend_from_slice(&key.to_bytes()); } } format!("{}", multibase::encode(multibase::Base::Base58Btc, &bytes)) } pub fn to_did_key(&self) -> String { format!("did:key:{}", self.to_multibase()) } pub fn from_did_key(did_key: &str) -> Result { if !did_key.starts_with("did:key:") || did_key.len() < 20 { return Err(anyhow!("does not look like a did:key: {}", did_key)); } let (key_type, bytes) = multibase::decode(&did_key[8..])?; ensure!( key_type == multibase::Base::Base58Btc, "base58btc-encoded key" ); // prefix bytes let prefix: [u8; 2] = [bytes[0], bytes[1]]; match prefix { MULTICODE_K256_BYTES => Ok(PubKey::K256(k256::ecdsa::VerifyingKey::from_sec1_bytes( &bytes[2..], )?)), MULTICODE_P256_BYTES => Ok(PubKey::P256(p256::ecdsa::VerifyingKey::from_sec1_bytes( &bytes[2..], )?)), _ => Err(anyhow!( "key type (multicodec) not handled when parsing DID key: {}", did_key )), } } pub fn to_bytes(&self) -> Vec { match self { PubKey::P256(key) => key.to_encoded_point(true).to_bytes().to_vec(), PubKey::K256(key) => key.to_bytes().to_vec(), } } pub fn ucan_keymaterial(&self) -> P256KeyMaterial { match self { PubKey::P256(key) => P256KeyMaterial(*key, None), PubKey::K256(_key) => unimplemented!(), } } } impl std::fmt::Display for PubKey { // TODO: what should this actually be, instead of multibase? the did:key representation? fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { write!(f, "{}", self.to_multibase()) } } #[test] fn test_did_secp256k1_p256() { // did:key secp256k1 test vectors from W3C // https://github.com/w3c-ccg/did-method-key/blob/main/test-vectors/secp256k1.json // via atproto repo let pairs = vec![ ( "9085d2bef69286a6cbb51623c8fa258629945cd55ca705cc4e66700396894e0c", "did:key:zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme", ), ( "f0f4df55a2b3ff13051ea814a8f24ad00f2e469af73c363ac7e9fb999a9072ed", "did:key:zQ3shtxV1FrJfhqE1dvxYRcCknWNjHc3c5X1y3ZSoPDi2aur2", ), ( "6b0b91287ae3348f8c2f2552d766f30e3604867e34adc37ccbb74a8e6b893e02", "did:key:zQ3shZc2QzApp2oymGvQbzP8eKheVshBHbU4ZYjeXqwSKEn6N", ), ( "c0a6a7c560d37d7ba81ecee9543721ff48fea3e0fb827d42c1868226540fac15", "did:key:zQ3shadCps5JLAHcZiuX5YUtWHHL8ysBJqFLWvjZDKAWUBGzy", ), ( "175a232d440be1e0788f25488a73d9416c04b6f924bea6354bf05dd2f1a75133", "did:key:zQ3shptjE6JwdkeKN4fcpnYQY3m9Cet3NiHdAfpvSUZBFoKBj", ), ]; // test decode/encode did:key for (_hex, did) in pairs.iter() { assert_eq!(did, &PubKey::from_did_key(did).unwrap().to_did_key()); } let p256_dids = vec![ "did:key:zDnaerx9CtbPJ1q36T5Ln5wYt3MQYeGRG5ehnPAmxcf5mDZpv", "did:key:zDnaerDaTF5BXEavCrfRZEk316dpbLsfPDZ3WJ5hRTPFU2169", ]; for did in p256_dids { assert_eq!(did, &PubKey::from_did_key(did).unwrap().to_did_key()); } } #[test] fn test_did_plc_examples() { // https://atproto.com/specs/did-plc let example_dids = vec![ "did:key:zDnaejYFhgFiVF89LhJ4UipACLKuqo6PteZf8eKDVKeExXUPk", "did:key:zDnaeSezF2TgCD71b5DiiFyhHQwKAfsBVqTTHRMvP597Z5Ztn", "did:key:zDnaeh9v2RmcMo13Du2d6pjUf5bZwtauYxj3n9dYjw4EZUAR7", "did:key:zDnaedvvAsDE6H3BDdBejpx9ve2Tz95cymyCAKF66JbyMh1Lt", ]; for did in example_dids { assert_eq!(did, &PubKey::from_did_key(did).unwrap().to_did_key()); } } #[test] fn test_signing() { let msg = b"you have found the secret message"; let keypair = KeyPair::new_random(); let sig_str = keypair.sign_bytes(msg); keypair.pubkey().verify_bytes(msg, &sig_str).unwrap(); // and with pubkey that has been serialized/deserialized let did_key = keypair.pubkey().to_did_key(); let pubkey = PubKey::from_did_key(&did_key).unwrap(); pubkey.verify_bytes(msg, &sig_str).unwrap(); } #[test] fn test_keypair_hex() { let before = KeyPair::new_random(); let after = KeyPair::from_hex(&before.to_hex()).unwrap(); assert!(before == after); }