public static byte[] signBySoft256(PrivateKey privateKey, byte[] data)
			throws Exception {
		byte[] result = null;
		Signature st = Signature.getInstance(BC_PROV_ALGORITHM_SHA256RSA, "BC");
		st.initSign(privateKey);
		st.update(data);
		result = st.sign();
		return result;
	}
public static byte [ ] signBySoft256 ( PrivateKey privateKey , byte [ ] data ) throws Exception { byte [ ] result = null ; Signature st = Signature . getInstance ( BC_PROV_ALGORITHM_SHA256RSA , "BC" ) ; st . initSign ( privateKey ) ; st . update ( data ) ; result = st . sign ( ) ; return result ; }
@param privateKey
@param data
@return
@throws Exception