Re: Issue with AES/DES RFC3211Wrap

The two variations require IVs, and generate them if one is not created,
so if you try the following instead:

public class WrapTest {

  private static final Key KEY_AES128 = new SecretKeySpec(Hex.decode("c794a7735f469c59cf9d7ddd8c65201d"), "AES");
  private static final Key KEY_DES = new SecretKeySpec(Hex.decode("8ccbbc15340b46c7cee6e5b6d6b6bc3e08ea38b55d3e08d9"), "DES");

  private static final byte[] PLAIN = "abcdefgh".getBytes();

  private static Provider prov = new BouncyCastleProvider();

  public static void main(String[] args) throws Exception {
// String res = wrap("AESWRAP", KEY_AES128, PLAIN); // unwrap("AESWRAP",
KEY_AES128, Hex.decode(res)); // res = wrap("DESEDEWRAP", KEY_DES,
PLAIN); // unwrap("DESEDEWRAP", KEY_DES, Hex.decode(res)); byte[][] res = wrap("AESRFC3211WRAP", KEY_AES128, PLAIN);
    unwrap("AESRFC3211WRAP", KEY_AES128, res);
    res = wrap("DESEDERFC3211WRAP", KEY_DES, PLAIN);
    unwrap("DESEDERFC3211WRAP", KEY_DES, res);
  }

  private static byte[][] wrap(String algo, Key privKey, byte[] data) throws Exception {
    Cipher engine = Cipher.getInstance(algo, prov);
    engine.init(Cipher.ENCRYPT_MODE, privKey);
    byte[] res = engine.doFinal(data);
    System.out.println(String.format("%s wrapped: %s", algo, Hex.toHexString(res)));
    return new byte[][] { engine.getIV(), res };
  }

  private static String unwrap(String algo, Key privKey, byte[][] data) throws Exception {
    Cipher engine = Cipher.getInstance(algo, prov);
    engine.init(Cipher.DECRYPT_MODE, privKey, new IvParameterSpec(data[0]));
    String res = new String(engine.doFinal(data[1]));
    System.out.println(String.format("%s unwrapped: %s", algo, res));
    return res;
  }
}

You should find it works. It raises an interesting point though - neither of these methods will work with data of more than 255 bytes, 
we should introduce a limit for these two. I'll have to add it to the list...

Regards,

David

On 13/09/18 19:31, MSKnete-S0/[email protected] wrote:
> Hi,
>  
> I have noticed that BC 1.60 changed the behavior of wrap ciphers in a
> way so that they can be also used in encrypt mode for wrapping data.
> This apparently works fine with AESWRAP and DESEDEWRAP. However when
> using AESRFC3211WRAP and DESEDERFC3211WRAP the wrapped data can't be
> unwrapped due to a javax.crypto.BadPaddingException. Please see the
> following class to demonstrate the issue:
>  
> import java.security.Key;
> import java.security.Provider;
> import java.util.Locale;
>  
> import javax.crypto.Cipher;
> import javax.crypto.spec.SecretKeySpec;
>  
> import org.bouncycastle.jce.provider.BouncyCastleProvider;
> import org.bouncycastle.util.encoders.Hex;
>  
> public class WrapTest {
>  
>   private static final Key KEY_AES128 = new
> SecretKeySpec(Hex.decode("c794a7735f469c59cf9d7ddd8c65201d"), "AES");
>   private static final Key KEY_DES = new
> SecretKeySpec(Hex.decode("8ccbbc15340b46c7cee6e5b6d6b6bc3e08ea38b55d3e08d9"),
> "DES");
>  
>   private static final byte[] PLAIN = "abcdefgh".getBytes();
>  
>   private static Provider prov = new BouncyCastleProvider();
>  
>   public static void main(String[] args) throws Exception {
>     String res = wrap("AESWRAP", KEY_AES128, PLAIN);
>     unwrap("AESWRAP", KEY_AES128, Hex.decode(res));
>     res = wrap("DESEDEWRAP", KEY_DES, PLAIN);
>     unwrap("DESEDEWRAP", KEY_DES, Hex.decode(res));
>  
>     res = wrap("AESRFC3211WRAP", KEY_AES128, PLAIN);
>     unwrap("AESRFC3211WRAP", KEY_AES128, Hex.decode(res));
>     res = wrap("DESEDERFC3211WRAP", KEY_DES, PLAIN);
>     unwrap("DESEDERFC3211WRAP", KEY_DES, Hex.decode(res));
>   }
>  
>   private static String wrap(String algo, Key privKey, byte[] data)
> throws Exception {
>     Cipher engine = Cipher.getInstance(algo, prov);
>     engine.init(Cipher.ENCRYPT_MODE, privKey);
>     String res =
> Hex.toHexString(engine.doFinal(data)).toUpperCase(Locale.ROOT);
>     System.out.println(String.format("%s wrapped: %s", algo, res));
>     return res;
>   }
>  
>   private static String unwrap(String algo, Key privKey, byte[] data)
> throws Exception {
>     Cipher engine = Cipher.getInstance(algo, prov);
>     engine.init(Cipher.DECRYPT_MODE, privKey);
>     String res = new String(engine.doFinal(data));
>     System.out.println(String.format("%s unwrapped: %s", algo, res));
>     return res;
>   }
> }
>  
> Is this an issue or have I just used the API wrong?
>  
> Kind Regards,
> Michael Schäfer