[英]Encrypting and Decrypting String using a Java equilavent of the C# CryptoStream
我正在寻找用Java开发用于移动平台操作系统的应用程序。
我已经在Windows环境的C#WPF中开发了一个应用程序。 我正在使用cryptostream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。
就个人而言,我喜欢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提供程序要痛苦的多,但是您可以根据需要将其用作提供程序。
看起来.net SymmetricAlgorithm
和BC的PaddedBufferedBlockCipher
默认为PKCS7填充,因此您可以使用默认值。
您可能需要检出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
尽管Cipher对象的初始化可能略有不同,但它们的使用方式几乎与上述示例完全相同。
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;
现在问题出在加密上。 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,但是由于某些原因,当我打印出加密的字符串时,它只会打印出一些垃圾,与C#创建的字符串完全不同。 以下是用于加密的代码
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。 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));
}
您必须对结果字节数组进行编码,然后才能将其转换为字符串。 上面的代码对我有用,而下面的是我的实际加密功能。
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;
}
请参阅关于Java中的CryptoStream .NET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"));
希望这可以帮助...
JK
Cemeron,整洁的代码!
我遇到了一个有趣的情况,我们的客户给IV的密码与密钥相同。
在尝试了遇到糟糕的填充异常的各种组合之后,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
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