用Java编写的密码算法类

王朝java/jsp·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

package data;

import java.security.*;

import javax.crypto.*;

import javax.crypto.spec.*;

import java.io.*;

/**

* Security 提供了一个安全算法类,其中包括对称密码算法和散列算法

*/

public final class Security

{

/**

* 对称加密方法

* @param byteSource 需要加密的数据

* @return 经过加密的数据

* @throws Exception

*/

public static byte[] symmetricEncrypto(byte[] byteSource) throws Exception

{

ByteArrayOutputStream baos = new ByteArrayOutputStream();

try

{

int mode = Cipher.ENCRYPT_MODE;

SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");

byte[] keyData = {1, 9, 8, 2, 0, 8, 2, 1};

DESKeySpec keySpec = new DESKeySpec(keyData);

Key key = keyFactory.generateSecret(keySpec);

Cipher cipher = Cipher.getInstance("DES");

cipher.init(mode, key);

int blockSize = cipher.getBlockSize();

int position = 0;

int length = byteSource.length;

boolean more = true;

while(more)

{

if(position + blockSize <= length)

{

baos.write(cipher.update(byteSource, position, blockSize));

position += blockSize;

}

else

{

more = false;

}

}

if(position < length)

{

baos.write(cipher.doFinal(byteSource, position, length - position));

}

else

{

baos.write(cipher.doFinal());

}

return baos.toByteArray();

}

catch(Exception e)

{

throw e;

}

finally

{

baos.close();

}

}

/**

* 对称解密方法

* @param byteSource 需要解密的数据

* @return 经过解密的数据

* @throws Exception

*/

public static byte[] symmetricDecrypto(byte[] byteSource) throws Exception

{

ByteArrayOutputStream baos = new ByteArrayOutputStream();

try

{

int mode = Cipher.DECRYPT_MODE;

SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");

byte[] keyData = {1, 9, 8, 2, 0, 8, 2, 1};

DESKeySpec keySpec = new DESKeySpec(keyData);

Key key = keyFactory.generateSecret(keySpec);

Cipher cipher = Cipher.getInstance("DES");

cipher.init(mode, key);

int blockSize = cipher.getBlockSize();

int position = 0;

int length = byteSource.length;

boolean more = true;

while(more)

{

if(position + blockSize <= length)

{

baos.write(cipher.update(byteSource, position, blockSize));

position += blockSize;

}

else

{

more = false;

}

}

if(position < length)

{

baos.write(cipher.doFinal(byteSource, position, length - position));

}

else

{

baos.write(cipher.doFinal());

}

return baos.toByteArray();

}

catch(Exception e)

{

throw e;

}

finally

{

baos.close();

}

}

/**

* 散列算法

* @param byteSource 需要散列计算的数据

* @return 经过散列计算的数据

* @throws Exception

*/

public static byte[] hashMethod(byte[] byteSource) throws Exception

{

try

{

MessageDigest currentAlgorithm = MessageDigest.getInstance("SHA-1");

currentAlgorithm.reset();

currentAlgorithm.update(byteSource);

return currentAlgorithm.digest();

}

catch(Exception e)

{

throw e;

}

}

}

 
 
 
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