Set default keysize for ECKeyPairGenerator to match OpenJDK (#883)

The default keysize used by the ECKeyPairGenerator, if not
explicitly initialized is changed from 256 to 384. This
change is made to match OpenJDK's behaviour.

An additional testcase is added to verify the default keysize.

Signed-off-by: Kostas Tsiounis <[email protected]>

Author: KostasTsiounis

src/main/java/com/ibm/crypto/plus/provider/ECKeyPairGenerator.java

@@ -21,8 +21,11 @@
 
 public final class ECKeyPairGenerator extends KeyPairGeneratorSpi {
 
+    private static final String EC_LEGACY_DEFAULT_KEYSIZE = "openjceplus.ec.legacy.defaultKeysize";
+    private static final boolean legacyECdefault = Boolean.parseBoolean(System.getProperty(EC_LEGACY_DEFAULT_KEYSIZE));
+
     private OpenJCEPlusProvider provider = null;
-    private int keysize = 256;
+    private int keysize = legacyECdefault? 256 : 384;
     private SecureRandom cryptoRandom = null;
     ECParameterSpec ecSpec;
     private ObjectIdentifier oid = null;

src/test/java/ibm/jceplus/junit/base/BaseTestECKeyPairGenerator.java

@@ -24,6 +24,7 @@
 import org.junit.jupiter.api.Test;
 import sun.security.util.InternalPrivateKey;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class BaseTestECKeyPairGenerator extends BaseTestJunit5 {
@@ -72,6 +73,19 @@ public void testECKeyGen_521() throws Exception {
         doECKeyGen(521);
     }
 
+    @Test
+    public void testECKeyGen_default() throws Exception {
+        KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", getProviderName());
+        KeyPair kp = kpg.generateKeyPair();
+        ECParameterSpec publicKeyParams = ((ECPublicKey) kp.getPublic()).getParams();
+        // The order of the curve's base point determines the key size
+        assertEquals(384, publicKeyParams.getOrder().bitLength(), "Default keysize is not as expected.");
+    
+        ECParameterSpec privateKeyParams = ((ECPrivateKey) kp.getPrivate()).getParams();
+        // The order of the curve's base point determines the key size
+        assertEquals(384, privateKeyParams.getOrder().bitLength(), "Default keysize is not as expected.");
+    }
+
     public void doECKeyGen(int keypairSize) throws Exception {
         kpg.initialize(keypairSize);
         KeyPair kp = kpg.generateKeyPair();