Merge pull request #592 from LNP-BP/feat/ecdsa-key-creation

Constructors for compressed and uncompressed ECDSA keys

src/util/address.rs

@@ -27,10 +27,7 @@
 //!
 //! // Generate random key pair
 //! let s = Secp256k1::new();
-//! let public_key = ecdsa::PublicKey {
+//! let public_key = ecdsa::PublicKey::new(s.generate_keypair(&mut thread_rng()).1);
-//!     compressed: true,
-//!     key: s.generate_keypair(&mut thread_rng()).1,
-//! };
 //!
 //! // Generate pay-to-pubkey-hash address
 //! let address = Address::p2pkh(&public_key, Network::Bitcoin);

src/util/bip32.rs

@@ -502,13 +502,7 @@ impl ExtendedPrivKey {
             depth: 0,
             parent_fingerprint: Default::default(),
             child_number: ChildNumber::from_normal_idx(0)?,
-            private_key: PrivateKey {
+            private_key: PrivateKey::from_slice(&hmac_result[..32], network)?,
-                compressed: true,
-                network: network,
-                key: secp256k1::SecretKey::from_slice(
-                    &hmac_result[..32]
-                ).map_err(Error::Ecdsa)?,
-            },
             chain_code: ChainCode::from(&hmac_result[32..]),
         })
     }
@@ -545,12 +539,8 @@ impl ExtendedPrivKey {
 
         hmac_engine.input(&endian::u32_to_array_be(u32::from(i)));
         let hmac_result: Hmac<sha512::Hash> = Hmac::from_engine(hmac_engine);
-        let mut sk = PrivateKey {
+        let mut sk = PrivateKey::from_slice(&hmac_result[..32], self.network)?;
-            compressed: true,
+        sk.key.add_assign(&self.private_key[..])?;
-            network: self.network,
-            key: secp256k1::SecretKey::from_slice(&hmac_result[..32]).map_err(Error::Ecdsa)?,
-        };
-        sk.key.add_assign(&self.private_key[..]).map_err(Error::Ecdsa)?;
 
         Ok(ExtendedPrivKey {
             network: self.network,
@@ -584,13 +574,7 @@ impl ExtendedPrivKey {
             parent_fingerprint: Fingerprint::from(&data[5..9]),
             child_number: endian::slice_to_u32_be(&data[9..13]).into(),
             chain_code: ChainCode::from(&data[13..45]),
-            private_key: PrivateKey {
+            private_key: PrivateKey::from_slice(&data[46..78], network)?,
-                compressed: true,
-                network: network,
-                key: secp256k1::SecretKey::from_slice(
-                    &data[46..78]
-                ).map_err(Error::Ecdsa)?,
-            },
         })
     }
 
@@ -662,11 +646,7 @@ impl ExtendedPubKey {
 
                 let hmac_result: Hmac<sha512::Hash> = Hmac::from_engine(hmac_engine);
 
-                let private_key = PrivateKey {
+                let private_key = PrivateKey::from_slice(&hmac_result[..32], self.network)?;
-                    compressed: true,
-                    network: self.network,
-                    key: secp256k1::SecretKey::from_slice(&hmac_result[..32])?,
-                };
                 let chain_code = ChainCode::from(&hmac_result[32..]);
                 Ok((private_key, chain_code))
             }
@@ -681,7 +661,7 @@ impl ExtendedPubKey {
     ) -> Result<ExtendedPubKey, Error> {
         let (sk, chain_code) = self.ckd_pub_tweak(i)?;
         let mut pk = self.public_key;
-        pk.key.add_exp_assign(secp, &sk[..]).map_err(Error::Ecdsa)?;
+        pk.key.add_exp_assign(secp, &sk[..])?;
 
         Ok(ExtendedPubKey {
             network: self.network,

src/util/contracthash.rs

@@ -329,25 +329,13 @@ mod tests {
         let (sk2, pk2) = secp.generate_keypair(&mut thread_rng());
         let (sk3, pk3) = secp.generate_keypair(&mut thread_rng());
 
-        let sk1 = PrivateKey {
+        let sk1 = PrivateKey::new(sk1, Network::Bitcoin);
-            key: sk1,
+        let sk2 = PrivateKey::new_uncompressed(sk2, Network::Bitcoin);
-            compressed: true,
+        let sk3 = PrivateKey::new(sk3, Network::Bitcoin);
-            network: Network::Bitcoin,
-        };
-        let sk2 = PrivateKey {
-            key: sk2,
-            compressed: false,
-            network: Network::Bitcoin,
-        };
-        let sk3 = PrivateKey {
-            key: sk3,
-            compressed: true,
-            network: Network::Bitcoin,
-        };
         let pks = [
-            PublicKey { key: pk1, compressed: true },
+            PublicKey::new(pk1),
-            PublicKey { key: pk2, compressed: false },
+            PublicKey::new_uncompressed(pk2),
-            PublicKey { key: pk3, compressed: true },
+            PublicKey::new(pk3),
         ];
         let contract = b"if bottle mt dont remembr drink wont pay";
 

src/util/ecdsa.rs

@@ -37,6 +37,23 @@ pub struct PublicKey {
 }
 
 impl PublicKey {
+    /// Constructs compressed ECDSA public key from the provided generic Secp256k1 public key
+    pub fn new(key: secp256k1::PublicKey) -> PublicKey {
+        PublicKey {
+            compressed: true,
+            key: key,
+        }
+    }
+
+    /// Constructs uncompressed (legacy) ECDSA public key from the provided generic Secp256k1
+    /// public key
+    pub fn new_uncompressed(key: secp256k1::PublicKey) -> PublicKey {
+        PublicKey {
+            compressed: false,
+            key: key,
+        }
+    }
+
     /// Returns bitcoin 160-bit hash of the public key
     pub fn pubkey_hash(&self) -> PubkeyHash {
         if self.compressed {
@@ -151,6 +168,26 @@ pub struct PrivateKey {
 }
 
 impl PrivateKey {
+    /// Constructs compressed ECDSA private key from the provided generic Secp256k1 private key
+    /// and the specified network
+    pub fn new(key: secp256k1::SecretKey, network: Network) -> PrivateKey {
+        PrivateKey {
+            compressed: true,
+            network: network,
+            key: key,
+        }
+    }
+
+    /// Constructs uncompressed (legacy) ECDSA private key from the provided generic Secp256k1
+    /// private key and the specified network
+    pub fn new_uncompressed(key: secp256k1::SecretKey, network: Network) -> PrivateKey {
+        PrivateKey {
+            compressed: false,
+            network: network,
+            key: key,
+        }
+    }
+
     /// Creates a public key from this private key
     pub fn public_key<C: secp256k1::Signing>(&self, secp: &Secp256k1<C>) -> PublicKey {
         PublicKey {
@@ -164,6 +201,14 @@ impl PrivateKey {
         self.key[..].to_vec()
     }
 
+    /// Deserialize a private key from a slice
+    pub fn from_slice(data: &[u8], network: Network) -> Result<PrivateKey, Error> {
+        Ok(PrivateKey::new(
+            secp256k1::SecretKey::from_slice(data)?,
+            network,
+        ))
+    }
+
     /// Format the private key to WIF format.
     pub fn fmt_wif(&self, fmt: &mut dyn fmt::Write) -> fmt::Result {
         let mut ret = [0; 34];