### Question:
KeyStoreBasedInternalCryptoProvider implements InternalCryptoProvider { public byte[] decrypt(byte[] ciphertext, String algorithm, String javaSecurityAPIProvider) throws CryptoException { try { Cipher cipher; if (StringUtils.isBlank(javaSecurityAPIProvider)) { cipher = Cipher.getInstance(algorithm); } else { cipher = Cipher.getInstance(algorithm, javaSecurityAPIProvider); } cipher.init(Cipher.DECRYPT_MODE, getPrivateKeyFromKeyStore()); if (log.isDebugEnabled()) { log.debug(String.format("Successfully decrypted data using the algorithm '%s' and the " + "Java Security API provider '%s'", algorithm, javaSecurityAPIProvider)); } return cipher.doFinal(ciphertext); } catch (NoSuchAlgorithmException | NoSuchPaddingException | NoSuchProviderException | BadPaddingException | IllegalBlockSizeException | InvalidKeyException | UnrecoverableKeyException | KeyStoreException e) { String errorMessage = String .format("An error occurred while decrypting using the algorithm : '%s'", algorithm); if (log.isDebugEnabled()) { log.debug(errorMessage, e); } throw new CryptoException(errorMessage, e); } } KeyStoreBasedInternalCryptoProvider(KeyStore keyStore, String keyAlias, String keyPassword); @Override byte[] encrypt(byte[] cleartext, String algorithm, String javaSecurityAPIProvider); byte[] decrypt(byte[] ciphertext, String algorithm, String javaSecurityAPIProvider);  }### Answer:
@Test(dataProvider = "encryptionAlgorithms") public void testDecrypting(String algorithm) throws Exception { int plaintextLength = 50; String plaintext = RandomStringUtils.random(plaintextLength); Cipher cipher = Cipher.getInstance(algorithm); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] ciphertext = cipher.doFinal(plaintext.getBytes(CHAR_ENCODING_UTF_8)); assertEquals(new String(jksCryptoProvider.decrypt(ciphertext, algorithm, null), CHAR_ENCODING_UTF_8), plaintext); }