使用C# CryptoStream的Java等价物对字符串进行加密和解密

Question

我正在考虑用Java为移动平台操作系统开发一个应用程序。

我已经为C#环境开发了一个Windows应用程序。我使用密码流，以便使用以下代码对字符串进行加密和解密。下面显示的代码仅用于加密

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());
    }

加密的字符串被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，并使用来自C#应用程序的相同加密密钥对字符串进行解密。

谢谢你的帮助。

Answer 1

就我个人而言，我喜欢BouncyCastle for Java crypto。下面的代码(使用BouncyCastle轻量级应用程序接口)应该可以做到这一点：

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没有JCE提供程序那么麻烦，但如果您愿意，可以将其用作提供程序。

看起来.net SymmetricAlgorithm和BC的PaddedBufferedBlockCipher都缺省为PKCS7填充，所以您应该可以使用缺省值。

Answer 2

你可能想看看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

它们的使用方法与上面的示例几乎完全相同，尽管Cipher对象的初始化可能略有不同。

Answer 3

我使用下面的代码在.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;
}

}