### Question:
Crypto { public static boolean verify(byte[] signature, byte[] message, byte[] publicKey) { try { if (signature.length != 64) { return false; } if (!Curve25519.isCanonicalSignature(signature)) { LOG.debug("Rejecting non-canonical signature"); return false; } if (!Curve25519.isCanonicalPublicKey(publicKey)) { LOG.debug("Rejecting non-canonical public key"); return false; } byte[] Y = new byte[32]; byte[] v = new byte[32]; System.arraycopy(signature, 0, v, 0, 32); byte[] h = new byte[32]; System.arraycopy(signature, 32, h, 0, 32); Curve25519.verify(Y, v, h, publicKey); MessageDigest digest = Crypto.sha256(); byte[] m = digest.digest(message); digest.update(m); byte[] h2 = digest.digest(Y); return Arrays.equals(h, h2); } catch (RuntimeException e) { LOG.error("Error verifying signature", e); return false; } } private  Crypto(); static SecureRandom getSecureRandom(); static MessageDigest getMessageDigest(String algorithm); static MessageDigest sha256(); static MessageDigest sha512(); static MessageDigest ripemd160(); static MessageDigest sha3(); static byte[] getKeySeed(String secretPhrase, byte[]... nonces); static byte[] getKeySeed(byte[] secretBytes, byte[]... nonces); static byte[] getPublicKey(byte[] keySeed); static byte[] getPublicKey(String secretPhrase); static byte[] getPrivateKey(byte[] keySeed); static byte[] getPrivateKey(String secretPhrase); static void curve(byte[] Z, byte[] k, byte[] P); static byte[] sign(byte[] message, String secretPhrase); static byte[] sign(byte[] message, byte[] keySeed); static boolean verify(byte[] signature, byte[] message, byte[] publicKey); static byte[] getSharedKey(byte[] myPrivateKey, byte[] theirPublicKey); static byte[] getSharedKey(byte[] myPrivateKey, byte[] theirPublicKey, byte[] nonce); static byte[] aesEncrypt(byte[] plaintext, byte[] key); static byte[] aesGCMEncrypt(byte[] plaintext, byte[] key); static byte[] aesDecrypt(byte[] ivCiphertext, byte[] key); static byte[] aesGCMDecrypt(byte[] ivCiphertext, byte[] key); static String rsEncode(long id); static long rsDecode(String rsString); static boolean isCanonicalPublicKey(byte[] publicKey); static boolean isCanonicalSignature(byte[] signature); static FBElGamalKeyPair getElGamalKeyPair(); static String elGamalDecrypt(String cryptogramm, FBElGamalKeyPair keyPair); static String elGamalEncrypt(String plainText, FBElGamalKeyPair keyPair);  }### Answer:
@Test public void testVerify() throws IOException { byte[] signature = Convert.parseHexString("f565212c53a668006fbdb12c512e51f7add8118e6573d5c7261e9f58944e5c0b0ae76275210b795915a3017852fe8bca1a3cd2d2b02b32a51e0e03b18e6335f8"); byte[] message =plain_data; byte[] publicKey = Crypto.getPublicKey(secretPhraseA); boolean expResult = true; boolean result = Crypto.verify(signature, message, publicKey); assertEquals(expResult, result); }