Merge pull request #302 from 0xcregis/301-ed25519-private-key-derivation

feat: ed25519 private key derivation
0xcregis · Dec 10, 2024 · 1a767e5 · 1a767e5
2 parents c5d0e38 + 85a69f7
commit 1a767e5
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Showing 6 changed files with 73 additions and 15 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/anychain-kms/Cargo.toml b/crates/anychain-kms/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "anychain-kms"
 description = "A Rust library providing Key Management Schema for AnyChain. Handles general security and signature algorithms."
-version = "0.1.13"
+version = "0.1.14"
 keywords = ["cryptography", "security", "signature", "algorithm"]
 categories = ["cryptography::cryptocurrencies"]
 

diff --git a/crates/anychain-kms/src/bip32/extended_key/extended_private_key.rs b/crates/anychain-kms/src/bip32/extended_key/extended_private_key.rs
@@ -8,7 +8,7 @@ use core::{
     fmt::{self, Debug},
     str::FromStr,
 };
-//use hmac::{Mac, NewMac};
+use curve25519_dalek::scalar::Scalar;
 use hmac::Mac;
 use subtle::{Choice, ConstantTimeEq};
 use zeroize::Zeroize;
@@ -24,9 +24,12 @@ const BIP39_DOMAIN_SEPARATOR: [u8; 12] = [
     0x42, 0x69, 0x74, 0x63, 0x6f, 0x69, 0x6e, 0x20, 0x73, 0x65, 0x65, 0x64,
 ];
 
-/// Extended private secp256k1 ECDSA signing key.
+/// Extended private secp256k1 signing key.
 pub type XprvSecp256k1 = ExtendedPrivateKey<libsecp256k1::SecretKey>;
 
+/// Extended private ed25519 signing key.
+pub type XprvEd25519 = ExtendedPrivateKey<Scalar>;
+
 /// Extended private keys derived using BIP32.
 ///
 /// Generic around a [`PrivateKey`] type. When the `secp256k1` feature of this

diff --git a/crates/anychain-kms/src/bip32/extended_key/extended_public_key.rs b/crates/anychain-kms/src/bip32/extended_key/extended_public_key.rs
@@ -96,7 +96,12 @@ where
             attrs: self.attrs.clone(),
             key_bytes: {
                 let mut key_bytes = [0u8; KEY_SIZE + 1];
-                key_bytes.copy_from_slice(&self.to_bytes());
+                let bytes = self.to_bytes();
+                let bytes = match bytes.len() {
+                    KEY_SIZE => [vec![0u8], bytes].concat(),
+                    _ => bytes,
+                };
+                key_bytes.copy_from_slice(&bytes);
                 key_bytes
             },
         }

diff --git a/crates/anychain-kms/src/bip32/mod.rs b/crates/anychain-kms/src/bip32/mod.rs
@@ -13,7 +13,7 @@ pub use extended_key::{
     extended_public_key::ExtendedPublicKey, ExtendedKey,
 };
 pub use extended_key::{
-    extended_private_key::XprvSecp256k1,
+    extended_private_key::{XprvEd25519, XprvSecp256k1},
     extended_public_key::{XpubEd25519, XpubSecp256k1},
 };
 pub use prefix::Prefix;

diff --git a/crates/anychain-kms/src/bip32/private_key.rs b/crates/anychain-kms/src/bip32/private_key.rs
@@ -1,10 +1,9 @@
 //! Trait for deriving child keys on a given type.
 
-use crate::bip32::{PublicKey, Result};
+use crate::bip32::{Error, PublicKey, Result, XprvEd25519, XprvSecp256k1};
 
-use crate::bip32::{Error, XprvSecp256k1};
-
-use libsecp256k1;
+use curve25519_dalek::{constants::ED25519_BASEPOINT_TABLE as G, scalar::Scalar};
+use group::GroupEncoding;
 
 /// Trait for key types which can be derived using BIP32.
 pub trait PrivateKey: Sized {
@@ -65,16 +64,51 @@ impl From<&XprvSecp256k1> for libsecp256k1::SecretKey {
     }
 }
 
+impl PrivateKey for Scalar {
+    type PublicKey = ed25519_dalek::PublicKey;
+
+    fn from_bytes(bytes: Vec<u8>) -> Result<Self> {
+        let mut sk = [0u8; 32];
+        sk.copy_from_slice(&bytes);
+        Ok(Scalar::from_bytes_mod_order(sk))
+    }
+
+    fn to_bytes(&self) -> Vec<u8> {
+        self.to_bytes().to_vec()
+    }
+
+    fn derive_child(&self, tweak: Vec<u8>) -> Result<Self> {
+        let mut _tweak = [0u8; 32];
+        _tweak.copy_from_slice(&tweak);
+        let tweak = Scalar::from_bytes_mod_order(_tweak);
+        Ok(self + tweak)
+    }
+
+    fn public_key(&self) -> Self::PublicKey {
+        let pk = (G * self).to_bytes();
+        ed25519_dalek::PublicKey::from_bytes(&pk).unwrap()
+    }
+}
+
+impl From<XprvEd25519> for Scalar {
+    fn from(xprv: XprvEd25519) -> Scalar {
+        Scalar::from(&xprv)
+    }
+}
+
+impl From<&XprvEd25519> for Scalar {
+    fn from(xprv: &XprvEd25519) -> Scalar {
+        *xprv.private_key()
+    }
+}
+
 #[cfg(test)]
 mod tests {
+    use super::{XprvEd25519, XprvSecp256k1};
     use hex_literal::hex;
 
-    //type XprvSecp256k1 = crate::bip32::ExtendedPrivateKey<k256::ecdsa::SigningKey>;
-
-    type XprvSecp256k1 = crate::bip32::ExtendedPrivateKey<libsecp256k1::SecretKey>;
-
     #[test]
-    fn secp256k1_derivation() {
+    fn test_secp256k1_derivation() {
         let seed = hex!(
             "fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a2
              9f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"
@@ -88,4 +122,20 @@ mod tests {
             "xprvA2nrNbFZABcdryreWet9Ea4LvTJcGsqrMzxHx98MMrotbir7yrKCEXw7nadnHM8Dq38EGfSh6dqA9QWTyefMLEcBYJUuekgW4BYPJcr9E7j".parse().unwrap()
         );
     }
+
+    #[test]
+    fn test_ed25519_derivation() {
+        let seed = hex!(
+            "fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a2
+             9f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"
+        );
+
+        let path = "m/0/2147483647'/1/2147483646'/2";
+        let xprv = XprvEd25519::new_from_path(seed, &path.parse().unwrap()).unwrap();
+
+        assert_eq!(
+            xprv,
+            "xprvA3jRL3NoAajWVMc6JWKPgQrxx5Xt6VVpgj8y6FMcBbseE4DkZEP8cfVqJQtQvyCqZpb39KZE5r7UUGwunJg9m3wksLj5x94cJv4ahGMarGU".parse().unwrap()
+        );
+    }
 }