What's wrong with IBM's JCE provider?

Question

I have a JCE test that works fine with all Sun JDKs I have tried, but fails with various IBM J9 JDKs (e.g. 1.6.0 build pwi3260sr8-20100409_01(SR8)). The exception below happens when the cipher is initialized in encrypt mode. Why can the IBM JCE not use its own private key? Am I missing something in my code?

  public void testBasicKeyGeneration() throws NoSuchAlgorithmException, 
      NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, 
      BadPaddingException, NoSuchProviderException, SignatureException {
      KeyPairGenerator generator = KeyPairGenerator.getInstance( "RSA" );
      generator.initialize( 2048 );
      KeyPair pair = generator.generateKeyPair();

      String data1 = "123456789012345678901234567890123456789012345678901234567890";
      Cipher cipher = Cipher.getInstance( "RSA" );
      cipher.init( Cipher.ENCRYPT_MODE, pair.getPrivate() );
      byte[] encrypted = cipher.doFinal( data1.getBytes() );

      cipher.init( Cipher.DECRYPT_MODE, pair.getPublic() );
      byte[] decrypted = cipher.doFinal( encrypted );
      String data2 = new String( decrypted );
      assertEquals( "en/decryption failed", data1, data2 );
  }

Here is the stack trace:

java.security.InvalidKeyException: Private key cannot be used to encrypt.
at com.ibm.crypto.provider.RSA.engineInit(Unknown Source)
at javax.crypto.Cipher.a(Unknown Source)
at javax.crypto.Cipher.a(Unknown Source)
at javax.crypto.Cipher.init(Unknown Source)
at javax.crypto.Cipher.init(Unknown Source)
at test.Test.testBasicKeyGeneration(LicenseHelperTest.java:56)

Answer 1

There is a solution, see http://www-01.ibm.com/support/docview.wss?uid=swg1IV18625

with the property

-Dcom.ibm.crypto.provider.DoRSATypeChecking=false

you can use private keys to encrypt data.