Add ECDSA key support (SECP256R1)

pom.xml

@@ -256,6 +256,11 @@
             <artifactId>gson</artifactId>
             <version>${gson.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.bouncycastle</groupId>
+            <artifactId>bcprov-jdk18on</artifactId>
+            <version>1.78.1</version>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>

src/main/java/org/biscuitsec/biscuit/crypto/Ed25519KeyPair.java

@@ -0,0 +1,87 @@
+package org.biscuitsec.biscuit.crypto;
+
+import biscuit.format.schema.Schema;
+import net.i2p.crypto.eddsa.EdDSAEngine;
+import net.i2p.crypto.eddsa.EdDSAPrivateKey;
+import net.i2p.crypto.eddsa.EdDSAPublicKey;
+import net.i2p.crypto.eddsa.spec.EdDSANamedCurveSpec;
+import net.i2p.crypto.eddsa.spec.EdDSANamedCurveTable;
+import net.i2p.crypto.eddsa.spec.EdDSAPrivateKeySpec;
+import net.i2p.crypto.eddsa.spec.EdDSAPublicKeySpec;
+import org.biscuitsec.biscuit.token.builder.Utils;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.SecureRandom;
+import java.security.Signature;
+
+class Ed25519KeyPair extends KeyPair {
+
+    private final EdDSAPrivateKey privateKey;
+    private final EdDSAPublicKey publicKey;
+
+    private static final EdDSANamedCurveSpec ed25519 = EdDSANamedCurveTable.getByName(EdDSANamedCurveTable.ED_25519);
+
+    public Ed25519KeyPair(byte[] bytes) {
+        EdDSAPrivateKeySpec privKeySpec = new EdDSAPrivateKeySpec(bytes, ed25519);
+        EdDSAPrivateKey privKey = new EdDSAPrivateKey(privKeySpec);
+
+        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(privKey.getA(), ed25519);
+        EdDSAPublicKey pubKey = new EdDSAPublicKey(pubKeySpec);
+
+        this.privateKey = privKey;
+        this.publicKey = pubKey;
+    }
+
+    public Ed25519KeyPair(SecureRandom rng) {
+        byte[] b = new byte[32];
+        rng.nextBytes(b);
+
+        EdDSAPrivateKeySpec privKeySpec = new EdDSAPrivateKeySpec(b, ed25519);
+        EdDSAPrivateKey privKey = new EdDSAPrivateKey(privKeySpec);
+
+        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(privKey.getA(), ed25519);
+        EdDSAPublicKey pubKey = new EdDSAPublicKey(pubKeySpec);
+
+        this.privateKey = privKey;
+        this.publicKey = pubKey;
+    }
+
+    public Ed25519KeyPair(String hex) {
+        this(Utils.hexStringToByteArray(hex));
+    }
+
+    public static java.security.PublicKey decode(byte[] data) {
+        return new EdDSAPublicKey(new EdDSAPublicKeySpec(data, ed25519));
+    }
+
+    public static Signature getSignature() throws NoSuchAlgorithmException {
+        return new EdDSAEngine(MessageDigest.getInstance(ed25519.getHashAlgorithm()));
+    }
+
+    @Override
+    public byte[] toBytes() {
+        return privateKey.getSeed();
+    }
+
+    @Override
+    public String toHex() {
+        return Utils.byteArrayToHexString(toBytes());
+    }
+
+    @Override
+    public java.security.PublicKey publicKey() {
+        return publicKey;
+    }
+
+    @Override
+    public PrivateKey private_key() {
+        return privateKey;
+    }
+
+    @Override
+    public PublicKey public_key() {
+        return new PublicKey(Schema.PublicKey.Algorithm.Ed25519, this.publicKey);
+    }
+}

src/main/java/org/biscuitsec/biscuit/crypto/KeyPair.java

@@ -1,106 +1,63 @@
 package org.biscuitsec.biscuit.crypto;
 
 
-import biscuit.format.schema.Schema;
 import biscuit.format.schema.Schema.PublicKey.Algorithm;
-import net.i2p.crypto.eddsa.EdDSAEngine;
-import org.biscuitsec.biscuit.token.builder.Utils;
-import net.i2p.crypto.eddsa.EdDSAPrivateKey;
-import net.i2p.crypto.eddsa.EdDSAPublicKey;
-import net.i2p.crypto.eddsa.spec.*;
+import net.i2p.crypto.eddsa.Utils;
 
-import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
 import java.security.Signature;
 
 /**
- * Private and public key
+ * Private and public key.
  */
-public final class KeyPair {
-    public final EdDSAPrivateKey private_key;
-    public final EdDSAPublicKey public_key;
+public abstract class KeyPair {
 
-    private static final int ED25519_PUBLIC_KEYSIZE = 32;
-    private static final int ED25519_PRIVATE_KEYSIZE = 64;
-    private static final int ED25519_SEED_SIZE = 32;
-    public static final EdDSANamedCurveSpec ed25519 = EdDSANamedCurveTable.getByName(EdDSANamedCurveTable.ED_25519);
-
-    public KeyPair() {
-        this(new SecureRandom());
+    public static KeyPair generate(Algorithm algorithm) {
+        return generate(algorithm, new SecureRandom());
     }
 
-    public KeyPair(final SecureRandom rng) {
-        byte[] b = new byte[32];
-        rng.nextBytes(b);
-
-        EdDSAPrivateKeySpec privKeySpec = new EdDSAPrivateKeySpec(b, ed25519);
-        EdDSAPrivateKey privKey = new EdDSAPrivateKey(privKeySpec);
-
-        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(privKey.getA(), ed25519);
-        EdDSAPublicKey pubKey = new EdDSAPublicKey(pubKeySpec);
-
-        this.private_key = privKey;
-        this.public_key = pubKey;
+    public static KeyPair generate(Algorithm algorithm, String hex) {
+        return generate(algorithm, Utils.hexToBytes(hex));
     }
 
-    public static KeyPair generate(Algorithm algorithm) {
-        return generate(algorithm, new SecureRandom());
+    public static KeyPair generate(Algorithm algorithm, byte[] bytes) {
+        if (algorithm == Algorithm.Ed25519) {
+            return new Ed25519KeyPair(bytes);
+        } else if (algorithm == Algorithm.SECP256R1) {
+            return new SECP256R1KeyPair(bytes);
+        } else {
+            throw new IllegalArgumentException("Unsupported algorithm");
+        }
     }
 
     public static KeyPair generate(Algorithm algorithm, SecureRandom rng) {
         if (algorithm == Algorithm.Ed25519) {
-            return new KeyPair(rng);
+            return new Ed25519KeyPair(rng);
+        } else if (algorithm == Algorithm.SECP256R1) {
+            return new SECP256R1KeyPair(rng);
         } else {
             throw new IllegalArgumentException("Unsupported algorithm");
         }
     }
 
     public static Signature generateSignature(Algorithm algorithm) throws NoSuchAlgorithmException {
         if (algorithm == Algorithm.Ed25519) {
-            return KeyPair.getSignature();
+            return Ed25519KeyPair.getSignature();
+        } else if (algorithm == Algorithm.SECP256R1) {
+            return SECP256R1KeyPair.getSignature();
         } else {
             throw new NoSuchAlgorithmException("Unsupported algorithm");
         }
     }
 
-    public byte[] toBytes() {
-        return this.private_key.getSeed();
-    }
-
-    public KeyPair(byte[] b) {
-        EdDSAPrivateKeySpec privKeySpec = new EdDSAPrivateKeySpec(b, ed25519);
-        EdDSAPrivateKey privKey = new EdDSAPrivateKey(privKeySpec);
-
-        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(privKey.getA(), ed25519);
-        EdDSAPublicKey pubKey = new EdDSAPublicKey(pubKeySpec);
-
-        this.private_key = privKey;
-        this.public_key = pubKey;
-    }
-
-    public String toHex() {
-        return Utils.byteArrayToHexString(this.toBytes());
-    }
-
-    public KeyPair(String hex) {
-        byte[] b = Utils.hexStringToByteArray(hex);
-
-        EdDSAPrivateKeySpec privKeySpec = new EdDSAPrivateKeySpec(b, ed25519);
-        EdDSAPrivateKey privKey = new EdDSAPrivateKey(privKeySpec);
+    public abstract byte[] toBytes();
 
-        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(privKey.getA(), ed25519);
-        EdDSAPublicKey pubKey = new EdDSAPublicKey(pubKeySpec);
+    public abstract String toHex();
 
-        this.private_key = privKey;
-        this.public_key = pubKey;
-    }
+    public abstract java.security.PublicKey publicKey();
 
-    public static Signature getSignature() throws NoSuchAlgorithmException {
-        return new EdDSAEngine(MessageDigest.getInstance(ed25519.getHashAlgorithm()));
-    }
+    public abstract java.security.PrivateKey private_key();
 
-    public PublicKey public_key() {
-        return new PublicKey(Schema.PublicKey.Algorithm.Ed25519, this.public_key);
-    }
+    public abstract PublicKey public_key();
 }

src/main/java/org/biscuitsec/biscuit/crypto/PublicKey.java

@@ -2,32 +2,46 @@
 
 import biscuit.format.schema.Schema;
 import biscuit.format.schema.Schema.PublicKey.Algorithm;
+import net.i2p.crypto.eddsa.EdDSAPublicKey;
 import org.biscuitsec.biscuit.error.Error;
 import org.biscuitsec.biscuit.token.builder.Utils;
 import com.google.protobuf.ByteString;
-import net.i2p.crypto.eddsa.EdDSAPublicKey;
-import net.i2p.crypto.eddsa.spec.EdDSAPublicKeySpec;
+import org.bouncycastle.jcajce.provider.asymmetric.ec.BCECPublicKey;
+
+import java.util.List;
 
-import static org.biscuitsec.biscuit.crypto.KeyPair.ed25519;
 
 public class PublicKey {
 
-    public final EdDSAPublicKey key;
+    public final java.security.PublicKey key;
     public final Algorithm algorithm;
 
-    public PublicKey(Algorithm algorithm, EdDSAPublicKey public_key) {
+    private static final List<Algorithm> SUPPORTED_ALGORITHMS = List.of(Algorithm.Ed25519, Algorithm.SECP256R1);
+
+    public PublicKey(Algorithm algorithm, java.security.PublicKey public_key) {
         this.key = public_key;
         this.algorithm = algorithm;
     }
 
     public PublicKey(Algorithm algorithm, byte[] data) {
-        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(data, ed25519);
-        this.key = new EdDSAPublicKey(pubKeySpec);
+        if (algorithm == Algorithm.Ed25519) {
+            this.key = Ed25519KeyPair.decode(data);
+        } else if (algorithm == Algorithm.SECP256R1) {
+            this.key = SECP256R1KeyPair.decode(data);
+        } else {
+            throw new IllegalArgumentException("Invalid algorithm");
+        }
         this.algorithm = algorithm;
     }
 
     public byte[] toBytes() {
-        return this.key.getAbyte();
+        if (algorithm == Algorithm.Ed25519) {
+            return ((EdDSAPublicKey) key).getAbyte();
+        } else if (algorithm == Algorithm.SECP256R1) {
+            return ((BCECPublicKey) key).getQ().getEncoded(true); // true = compressed
+        } else {
+            throw new IllegalArgumentException("Invalid algorithm");
+        }
     }
 
     public String toHex() {
@@ -36,8 +50,13 @@ public String toHex() {
 
     public PublicKey(Algorithm algorithm, String hex) {
         byte[] data = Utils.hexStringToByteArray(hex);
-        EdDSAPublicKeySpec pubKeySpec = new EdDSAPublicKeySpec(data, ed25519);
-        this.key = new EdDSAPublicKey(pubKeySpec);
+        if (algorithm == Algorithm.Ed25519) {
+            this.key = Ed25519KeyPair.decode(data);
+        } else if (algorithm == Algorithm.SECP256R1) {
+            this.key = SECP256R1KeyPair.decode(data);
+        } else {
+            throw new IllegalArgumentException("Invalid algorithm");
+        }
         this.algorithm = algorithm;
     }
 
@@ -49,10 +68,9 @@ public Schema.PublicKey serialize() {
     }
 
     static public PublicKey deserialize(Schema.PublicKey pk) throws Error.FormatError.DeserializationError {
-        if(!pk.hasAlgorithm() || !pk.hasKey() || pk.getAlgorithm() != Algorithm.Ed25519) {
+        if(!pk.hasAlgorithm() || !pk.hasKey() || !SUPPORTED_ALGORITHMS.contains(pk.getAlgorithm())) {
             throw new Error.FormatError.DeserializationError("Invalid public key");
         }
-
         return new PublicKey(pk.getAlgorithm(), pk.getKey().toByteArray());
     }
 
@@ -73,6 +91,12 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return "ed25519/" + toHex().toLowerCase();
+        if (algorithm == Algorithm.Ed25519) {
+            return "ed25519/" + toHex().toLowerCase();
+        } else if (algorithm == Algorithm.SECP256R1) {
+            return "secp256r1/" + toHex().toLowerCase();
+        } else {
+            return null;
+        }
     }
 }