### Question:
HMACSHA256 { private HMACSHA256() {} private  HMACSHA256(); static Bytes authenticate(Bytes message, Key key); static byte[] authenticate(byte[] message, Key key); static boolean verify(Bytes authenticator, Bytes in, Key key); static boolean verify(byte[] authenticator, byte[] in, Key key);  }### Answer:
@Test void testHmacsha256() { HMACSHA256.Key key = HMACSHA256.Key.random(); Bytes authenticator = HMACSHA256.authenticate(Bytes.fromHexString("deadbeef"), key); assertTrue(HMACSHA256.verify(authenticator, Bytes.fromHexString("deadbeef"), key)); }