我正在考虑用 Java 为移动平台操作系统开发应用程序。
我已经在 Windows 环境下使用 C# WPF 开发了一个应用程序。我正在使用加密流来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());
}
加密的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读取字符串并使用 C# 应用程序中的相同加密密钥解密该字符串。
感谢您的帮助。
就个人而言，我喜欢用于 Java 加密的 BouncyCastle。这段代码（使用 BouncyCastle 轻量级 API）应该可以解决问题：
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 提供程序的东西要轻松一些，但如果您愿意，您可以将它用作提供程序。
看起来 .net
SymmetricAlgorithmPaddedBufferedBlockCipher您可能想查看 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，尽管 Cipher 对象的初始化可能略有不同。
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;
}
}
我已经设法解决了这个问题。现在解密工作正常。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。我使用了相同的代码，只是将密码从解密模式更改为加密模式，但由于某种原因，当我打印出加密字符串时，它只是打印出一堆垃圾，与 C# 创建的字符串完全不同。以下是加密代码
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。谢谢
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，您必须对其进行编码。上面的代码对我来说很有效，而我的实际加密函数如下。
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;
}
参见答案#5 相当于 Java 中的 CryptoStream .NET？
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"));
希望这有帮助...
JK
塞梅隆， 那里有整洁的代码！
我遇到了一个有趣的情况，我们的客户给出的 IV 与 key 相同。
在尝试了各种组合后，我遇到了不良填充异常，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