public static PublicKey getRSAPublicKey(PrivateKey privateKey) {
		if (privateKey instanceof RSAPrivateCrtKey) {
			final RSAPrivateCrtKey privk = (RSAPrivateCrtKey) privateKey;
			return getRSAPublicKey(privk.getModulus(), privk.getPublicExponent());
		}
		return null;
	}
@Test
	public void getRSAPublicKeyTest(){
		final KeyPair keyPair = KeyUtil.generateKeyPair("RSA");
		final PrivateKey aPrivate = keyPair.getPrivate();
		final PublicKey rsaPublicKey = KeyUtil.getRSAPublicKey(aPrivate);
		assertEquals(rsaPublicKey, keyPair.getPublic());
	}