Question

我正在研究用Java开发移动平台操作系统的应用程序。

我已经在C＃WPF中为Windows环境开发了一个应用程序。我使用cryptostream以使用以下代码加密和解密字符串。下面显示的代码只是加密

public string encrypt(string encryptionString)
    {
        byte[] clearTextBytes = Encoding.UTF8.GetBytes(encryptionString);

        SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();

        MemoryStream ms = new MemoryStream();
        byte[] rgbIV = Encoding.ASCII.GetBytes("ryojvlzmdalyglrj");
        byte[] key = Encoding.ASCII.GetBytes("hcxilkqbbhczfeultgbskdmaunivmfuo");
        CryptoStream cs = new CryptoStream(ms, rijn.CreateEncryptor(key, rgbIV), CryptoStreamMode.Write);

        cs.Write(clearTextBytes, 0, clearTextBytes.Length);

        cs.Close();

        return Convert.ToBase64String(ms.ToArray());
    }

加密字符串存储在在线数据库中。我需要做的是让java应用程序能够从数据库中读取字符串并使用C＃应用程序中相同的加密密钥解密字符串。

感谢您的帮助。

Answer 1

就个人而言，我喜欢BouncyCastle来获取Java加密。这段代码（使用BouncyCastle轻量级API）可以解决这个问题：

String decrypt(byte[] cryptoBytes, byte[] key, byte[] iv) {
    BlockCipher cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine()));
    cipher.init(false, new ParametersWithIV(new KeyParameter(key), iv));
    byte[] out = new byte[cipher.getOutputSize(cryptoBytes.length)];
    int offset = cipher.processBytes(cryptoBytes, 0, cryptoBytes.length, out, 0);
    cipher.doFinal(out, offset);
    return new String(out);
}

我发现BouncyCastle的轻量级API比JCE提供程序的东西更少痛苦，但如果你愿意，可以将它作为提供者使用。

看起来.net SymmetricAlgorithm和BC的PaddedBufferedBlockCipher默认为PKCS7填充，所以你应该可以使用默认值。

Answer 2

您可能需要查看javax.crypto.CipherInputStream和javax.crypto.CipherOutputStream。

http://download.oracle.com/javase/1.5.0/docs/api/javax/crypto/CipherInputStream.html http://download.oracle.com/javase/1.5.0/docs/api/javax/crypto/CipherOutputStream.html

它们的使用方式几乎与上面的示例完全相同，但Cipher对象的初始化可能略有不同。

Answer 3

我使用以下内容在.net和java

之间进行加密

在.net中我使用：

    /// <summary>
    /// DES Encryption method - used to encryp password for the java.
    /// </summary>
    /// <param name="plainText"></param>
    /// <returns></returns>
    public string EncryptData(string plainText)
    {
        DES des = new DESCryptoServiceProvider();
        des.Mode = CipherMode.ECB;
        des.Padding = PaddingMode.PKCS7;

        des.Key = Encoding.UTF8.GetBytes(_secretPhrase.Substring(0, 8));
        des.IV = Encoding.UTF8.GetBytes(_secretPhrase.Substring(0, 8));

        byte[] bytes = Encoding.UTF8.GetBytes(plainText);
        byte[] resultBytes = des.CreateEncryptor().TransformFinalBlock(bytes, 0, bytes.Length);

        return Convert.ToBase64String(resultBytes);
    }

    /// <summary>
    /// DES Decryption method - used the decrypt password encrypted in java
    /// </summary>
    /// <param name="encryptedText"></param>
    /// <returns></returns>
    public string DecryptData(string encryptedText)
    {
        DES des = new DESCryptoServiceProvider();
        des.Mode = CipherMode.ECB;
        des.Padding = PaddingMode.PKCS7;
        des.Key = Encoding.UTF8.GetBytes(_secretPhrase.Substring(0, 8));
        des.IV = System.Text.Encoding.UTF8.GetBytes(_secretPhrase.Substring(0, 8));

        byte[] bytes = Convert.FromBase64String(encryptedText);
        byte[] resultBytes = des.CreateDecryptor().TransformFinalBlock(bytes, 0, bytes.Length);

        return Encoding.UTF8.GetString(resultBytes);
    }

在java中我使用：

公共类CryptoUtil {

public static final Logger LOG = Logger.getLogger(CryptoUtil.class);

private Cipher cipher = null;

private SecretKey key = null;

// This variable holds a string based on which a unique key will be generated
private static final String SECRET_PHRASE = "SECRET PHRASE GOES HERE";

// Charset will be used to convert between String and ByteArray
private static final String CHARSET = "UTF8";

 // The algorithm to be used for encryption/decryption DES(Data Encryption Standard)
private static final String ALGORITHM = "DES";

public CryptoUtil() throws DDICryptoException {
    try {
        // generate a key from SecretKeyFactory
        DESKeySpec keySpec = new DESKeySpec(SECRET_PHRASE.getBytes(CHARSET));
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
        key = keyFactory.generateSecret(keySpec);
        cipher = Cipher.getInstance(ALGORITHM);
    } catch (Exception e) {
        LOG.error(e);
        throw new DDICryptoException(e);
    }
}


/**
 * This method takes a plain text string and returns encrypted string using DES algorithm
 * @param plainText
 * @return String
 * @throws DDICryptoException
 */
public String encrypt(String plainText) throws DDICryptoException {
    String encryptedString = null;
    try {
        // initializes the cipher with a key.
        cipher.init(Cipher.ENCRYPT_MODE, key);

        byte[] plainTextAsUTF8 = plainText.getBytes(CHARSET);

        // decrypts data in a single-part or multi-part operation
        byte[] encryptedBytes = cipher.doFinal(plainTextAsUTF8);

        encryptedString = new sun.misc.BASE64Encoder().encode(encryptedBytes);
    } catch (Exception e) {
        LOG.error(e);
        throw new DDICryptoException(e);

    }
    return encryptedString;

}

/**
 * This method takes a plain text string and returns encrypted string using DES algorithm
 * @param encryptedString
 * @return
 * @throws DDICryptoException
 */
public String decrypt(String encryptedString) throws DDICryptoException {    
    String decryptedString = null;
    try {
        byte[] decodedString = new sun.misc.BASE64Decoder().decodeBuffer(encryptedString);

        // initializes the cipher with a key.
        cipher.init(Cipher.DECRYPT_MODE, key);

        // decrypts data in a single-part or multi-part operation
        byte[] decryptedBytes = cipher.doFinal(decodedString);
        decryptedString = new String(decryptedBytes, CHARSET);
    } catch (Exception e) {
        LOG.error(e);
        throw new DDICryptoException(e);
    }
    return decryptedString;
}

}

Answer 4

我有点设法解决了这个问题。解密现在工作正常。使用以下代码

    String plainPassword = "";
            try
            {
                SecretKeySpec key = new SecretKeySpec("hcxilkqbbhczfeultgbskdmaunivmfuo".getBytes("US-ASCII"), "AES");

                IvParameterSpec iv = new IvParameterSpec("ryojvlzmdalyglrj".getBytes("US_ASCII"));

                Cipher cipher = Cipher.getInsta

nce("AES/CBC/PKCS7Padding");

            cipher.init(Cipher.DECRYPT_MODE, key, iv);

            byte[] encoded = cipher.doFinal(Base64.decodeBase64(encryptedPassword.getBytes()));
            plainPassword = new String(encoded);
        }
        catch (Exception ex)
        {
            Log.d("Decryption Error", ex.toString());
        }

        return plainPassword;

现在的问题是加密。我使用相同的代码，除了将密码从解密模式更改为加密模式，但由于某种原因，当我打印出加密的字符串时，它只会打印出一堆垃圾，这与C＃创建的字符串完全不同。下面是加密的代码

public String encrypt(String plainPasword)
    {
        String password = "";
        try
        {
            SecretKeySpec key = new SecretKeySpec("hcxilkqbbhczfeultgbskdmaunivmfuo".getBytes("US-ASCII"), "AES");

            IvParameterSpec iv = new IvParameterSpec("ryojvlzmdalyglrj".getBytes("US_ASCII"));

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");

            cipher.init(Cipher.ENCRYPT_MODE, key, iv);

            byte[] encoded = cipher.doFinal(plainPasword.getBytes());
            password = new String(encoded);


        }
        catch (Exception ex)
        {
            Log.d("Encryption Error", ex.toString());
        }
        return password;
    }

这似乎有什么问题我无法解决这个问题。感谢

Answer 5

        StringBuffer strbuf = new StringBuffer(buf.length * 2);
        int i;

        for (i = 0; i < buf.length; i++) {
            if (((int) buf[i] & 0xff) < 0x10) {
                strbuf.append("0");
            }

            strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
        }

在将结果字节数组转换为字符串之前，必须对其进行编码。上面的代码为我做了诀窍，而我的实际加密函数低于。

public String encrypt(String data) throws Exception{
    try {
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        Key k = new SecretKeySpec(key.getBytes(), 0, key.length(), "AES");

        // Calculate ciphertext size.
        int blocksize = 16;
        int ciphertextLength = 0;
        int remainder = data.getBytes().length % blocksize;
        if (remainder == 0) {
            ciphertextLength = data.getBytes().length + blocksize;
        } else {
            ciphertextLength = data.getBytes().length - remainder + blocksize;
        }


        cipher.init(Cipher.ENCRYPT_MODE, k);
        byte[] buf = new byte[ciphertextLength];
        cipher.doFinal(data.getBytes(), 0, data.length(), buf, 0);

        StringBuffer strbuf = new StringBuffer(buf.length * 2);
        int i;

        for (i = 0; i < buf.length; i++) {
            if (((int) buf[i] & 0xff) < 0x10) {
                strbuf.append("0");
            }

            strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
        }
        return strbuf.toString();
    } catch (Exception e) {
        Logger.logException(e);
    }
    return null;
}

Answer 6

见Equivalent to CryptoStream .NET in Java?上的答案＃5

请务必阅读底部的评论......

KeySpec ks = new DESKeySpec("key12345".getBytes("UTF-8")); SecretKey key = SecretKeyFactory.getInstance("DES").generateSecret(ks); IvParameterSpec iv = new IvParameterSpec( Hex.decodeHex("1234567890ABCDEF".toCharArray())); Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, key, iv); byte[] decoded = cipher.doFinal(Base64.decodeBase64("B3xogi/Qfsc=")); System.out.println("Decoded: " + new String(decoded, "UTF-8"));

希望这会有所帮助......
JK

Answer 7

Cemeron，那里整洁的代码！

我遇到了一个有趣的情况，我们的客户将 IV 与键相同。

尝试了各种组合，我得到了不良的填充异常，有效的解决方案是

byte[] iv=new byte[8]; // assuming RC2
System.arraycopy(key.getBytes(), 0, iv, 0, key.getBytes().length > iv.length ? key.getBytes().length);

// Now decrypt and hopefully this should work

使用Java等效的C＃CryptoStream加密和解密字符串

7 个答案: