feat: More support for compressed EC keys

danubetech · Dec 4, 2024 · 7e17bd2 · 7e17bd2
1 parent e0696af
commit 7e17bd2
Showing 1 changed file with 24 additions and 7 deletions.
diff --git a/src/main/java/com/danubetech/keyformats/PublicKeyBytes.java b/src/main/java/com/danubetech/keyformats/PublicKeyBytes.java
@@ -229,13 +229,22 @@ public static byte[] P_384PublicKey_to_bytes(ECPublicKey publicKey) {
 
 	public static ECPublicKey bytes_to_P_384PublicKey(byte[] publicKeyBytes) {
 
-		if (publicKeyBytes.length != 97) throw new IllegalArgumentException("Expected 97 bytes instead of " + publicKeyBytes.length);
+		if (publicKeyBytes.length != 49 && publicKeyBytes.length != 97) throw new IllegalArgumentException("Expected 97 bytes instead of " + publicKeyBytes.length);
 
 		byte[] x = new byte[48];
 		byte[] y = new byte[48];
 		if (publicKeyBytes[0] != 4) throw new IllegalArgumentException("Expected 0x04 as first byte instead of " + publicKeyBytes[0] + " (length: " + publicKeyBytes.length + ")");
-		System.arraycopy(publicKeyBytes, 1, x, 0, x.length);
-		System.arraycopy(publicKeyBytes, 1+x.length, y, 0, y.length);
+
+		if (publicKeyBytes.length == 97) {
+			System.arraycopy(publicKeyBytes, 1, x, 0, x.length);
+			System.arraycopy(publicKeyBytes, 1+x.length, y, 0, y.length);
+		} else {
+			System.arraycopy(publicKeyBytes, 1, x, 0, x.length);
+			ECNamedCurveParameterSpec ecNamedCurveParameterSpec = ECNamedCurveTable.getParameterSpec("secp384r1");
+			org.bouncycastle.math.ec.ECPoint bcEcPoint = ecNamedCurveParameterSpec.getCurve().decodePoint(x);
+			x = bcEcPoint.getRawXCoord().getEncoded();
+			y = bcEcPoint.getRawYCoord().getEncoded();
+		}
 
 		ECPublicKey publicKey;
 		try {
@@ -274,13 +283,21 @@ public static byte[] P_521PublicKey_to_bytes(ECPublicKey publicKey) {
 
 	public static ECPublicKey bytes_to_P_521PublicKey(byte[] publicKeyBytes) {
 
-		if (! (publicKeyBytes.length >= 129 && publicKeyBytes.length <= 133)) throw new IllegalArgumentException("Expected >=129 and <=133 bytes instead of " + publicKeyBytes.length);
+		if ((! (publicKeyBytes.length >= 65 && publicKeyBytes.length <= 67)) && (! (publicKeyBytes.length >= 129 && publicKeyBytes.length <= 133))) throw new IllegalArgumentException("Expected >=65 and <=67 OR >=129 and <=133 bytes instead of " + publicKeyBytes.length);
 
 		byte[] x = new byte[(publicKeyBytes.length-1)/2];
 		byte[] y = new byte[(publicKeyBytes.length-1)/2];
-		if (publicKeyBytes[0] != 4) throw new IllegalArgumentException("Expected 0x04 as first byte instead of " + publicKeyBytes[0] + " (length: " + publicKeyBytes.length + ")");
-		System.arraycopy(publicKeyBytes, 1, x, 0, x.length);
-		System.arraycopy(publicKeyBytes, 1+x.length, y, 0, y.length);
+
+		if (publicKeyBytes.length >= 129 && publicKeyBytes.length <= 133) {
+			System.arraycopy(publicKeyBytes, 1, x, 0, x.length);
+			System.arraycopy(publicKeyBytes, 1+x.length, y, 0, y.length);
+		} else {
+			System.arraycopy(publicKeyBytes, 1, x, 0, x.length);
+			ECNamedCurveParameterSpec ecNamedCurveParameterSpec = ECNamedCurveTable.getParameterSpec("secp384r1");
+			org.bouncycastle.math.ec.ECPoint bcEcPoint = ecNamedCurveParameterSpec.getCurve().decodePoint(x);
+			x = bcEcPoint.getRawXCoord().getEncoded();
+			y = bcEcPoint.getRawYCoord().getEncoded();
+		}
 
 		ECPublicKey publicKey;
 		try {