@Override
    public byte[] sign(PrivateKey key, byte[] data) throws CryptoException {
        return ecdsaSignToBytes((ECPrivateKey) key, data);
    }
@ Override public byte [ ] sign ( PrivateKey key , byte [ ] data ) throws CryptoException { return ecdsaSignToBytes ( ( ECPrivateKey ) key , data ) ; }
@throws ClassCastException if the supplied private key is not of type {@link ECPrivateKey}.