/** * Creates signature for data. * * @param alg Algorithm. * @param prv Provider. * @param key Private key. * @param data Data. * @return Signature. * @throws GeneralSecurityException If any exception occurs while signature creation. */ public static byte[] createSignature(String alg, String prv, PrivateKey key, byte[] data) throws GeneralSecurityException { assert !F.isEmpty(alg); assert !F.isEmpty(prv); assert key != null; assert data != null; Signature sign = Signature.getInstance(alg, prv); sign.initSign(key); sign.update(data); return sign.sign(); }