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use crate::{ didcore::*, ed25519::Ed25519KeyPair, traits::{DIDCore, Ecdsa, Fingerprint, Generate, KeyMaterial}, AsymmetricKey, Error, KeyPair, }; use super::{generate_seed, Ecdh}; use std::convert::TryInto; use x25519_dalek::{PublicKey, StaticSecret}; pub type X25519KeyPair = AsymmetricKey<PublicKey, StaticSecret>; impl Generate for X25519KeyPair { fn new_with_seed(seed: &[u8]) -> Self { let secret_seed = generate_seed(&seed.to_vec()).expect("invalid seed"); let sk = StaticSecret::from(secret_seed); let pk: PublicKey = (&sk).try_into().expect("invalid public key"); X25519KeyPair { public_key: pk, secret_key: Some(sk), } } fn from_public_key(public_key: &[u8]) -> Self { let mut pk: [u8; 32] = [0; 32]; pk.clone_from_slice(public_key); X25519KeyPair { public_key: PublicKey::from(pk), secret_key: None, } } fn new() -> Self { Self::new_with_seed(vec![].as_slice()) } fn from_secret_key(secret_key: &[u8]) -> Self { let sized_data: [u8; 32] = clone_into_array(&secret_key[..32]); let sk = StaticSecret::from(sized_data); let pk: PublicKey = (&sk).try_into().expect("invalid public key"); X25519KeyPair { public_key: pk, secret_key: Some(sk), } } } impl KeyMaterial for X25519KeyPair { fn public_key_bytes(&self) -> Vec<u8> { self.public_key.to_bytes().to_vec() } fn private_key_bytes(&self) -> Vec<u8> { self.secret_key.as_ref().unwrap().to_bytes().to_vec() } } impl Ecdh for X25519KeyPair { fn key_exchange(&self, key: &Self) -> Vec<u8> { match &(self.secret_key) { Some(x) => x.diffie_hellman(&key.public_key).as_bytes().to_vec(), None => panic!("secret key not present"), } } } impl Ecdsa for X25519KeyPair { fn sign(&self, _: crate::Payload) -> Vec<u8> { unimplemented!("ECDSA is not supported for this key type") } fn verify(&self, _: crate::Payload, _: &[u8]) -> Result<(), Error> { unimplemented!("ECDSA is not supported for this key type") } } impl From<Ed25519KeyPair> for X25519KeyPair { fn from(key: Ed25519KeyPair) -> Self { key.get_x25519() } } impl DIDCore for X25519KeyPair { fn get_verification_methods(&self, config: Config, controller: &str) -> Vec<VerificationMethod> { vec![VerificationMethod { id: format!("{}#{}", controller, self.fingerprint()), key_type: match config.use_jose_format { false => "X25519KeyAgreementKey2019".into(), true => "OKP".into(), }, controller: controller.to_string(), public_key: Some(match config.use_jose_format { false => KeyFormat::Base58(bs58::encode(self.public_key_bytes()).into_string()), true => KeyFormat::JWK(JWK { key_type: "OKP".into(), curve: "X25519".into(), x: Some(base64::encode_config(self.public_key_bytes(), base64::URL_SAFE_NO_PAD)), ..Default::default() }), }), private_key: self.secret_key.as_ref().map(|_| match config.use_jose_format { false => KeyFormat::Base58(bs58::encode(self.private_key_bytes()).into_string()), true => KeyFormat::JWK(JWK { key_type: "OKP".into(), curve: "X25519".into(), x: Some(base64::encode_config(self.public_key_bytes(), base64::URL_SAFE_NO_PAD)), d: Some(base64::encode_config(self.private_key_bytes(), base64::URL_SAFE_NO_PAD)), ..Default::default() }), }), ..Default::default() }] } fn get_did_document(&self, config: Config) -> Document { let fingerprint = self.fingerprint(); let controller = format!("did:key:{}", fingerprint.clone()); let vm = self.get_verification_methods(config, &controller); Document { context: "https://www.w3.org/ns/did/v1".to_string(), id: controller.to_string(), key_agreement: Some(vm.iter().map(|x| x.id.to_string()).collect()), authentication: None, assertion_method: None, capability_delegation: None, capability_invocation: None, verification_method: vm, } } } impl Fingerprint for X25519KeyPair { fn fingerprint(&self) -> String { let codec: &[u8] = &[0xec, 0x1]; let data = [codec, self.public_key.as_bytes()].concat(); format!("z{}", bs58::encode(data).into_string()) } } impl From<X25519KeyPair> for KeyPair { fn from(key_pair: X25519KeyPair) -> Self { KeyPair::X25519(key_pair) } } fn clone_into_array<A, T>(slice: &[T]) -> A where A: Sized + Default + AsMut<[T]>, T: Clone, { let mut a = Default::default(); <A as AsMut<[T]>>::as_mut(&mut a).clone_from_slice(slice); a } #[cfg(test)] pub mod test { use super::*; #[test] fn test_demo() { let alice = X25519KeyPair::new_with_seed(vec![].as_slice()); let bob = X25519KeyPair::new_with_seed(vec![].as_slice()); let ex1 = alice.key_exchange(&bob); let ex2 = bob.key_exchange(&alice); assert_eq!(ex1, ex2); } }