### Question:
Hash { public static Bytes32 keccak256(final Bytes input) { return Bytes32.wrap(digestUsingAlgorithm(input, KECCAK256_ALG)); } private  Hash(); static Bytes32 sha256(final Bytes input); static Bytes32 keccak256(final Bytes input); static Bytes ripemd160(final Bytes input); static Bytes blake2bf(final Bytes input); static final String KECCAK256_ALG; }### Answer:
@Test public void keccak256Hash() { final Bytes resultHorse = Hash.keccak256(Bytes.wrap("horse".getBytes(UTF_8))); assertThat(resultHorse).isEqualTo(Bytes.fromHexString(horseKeccak256)); final Bytes resultCow = Hash.keccak256(Bytes.wrap("cow".getBytes(UTF_8))); assertThat(resultCow).isEqualTo(Bytes.fromHexString(cowKeccak256)); }