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public static String DESDecrypt(String data, String key, String encoding)
{
String edata = data;
try
{
MessageDigest digest = MessageDigest.getInstance("MD5");
digest.update(key.getBytes(encoding));
DESedeKeySpec dks = new DESedeKeySpec(convert16To24(digest.digest()));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DESede");
SecretKey securekey = keyFactory.generateSecret(dks);
Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE , securekey, new SecureRandom());
if (!data.endsWith( "=" ))
{
data = URLDecoder.decode(data, encoding);
}
edata = new String(cipher.doFinal(BASE64Decrypt(data)), encoding);
}
catch (Exception e)
{
e.printStackTrace();
}
return edata;
}
/**
* BASE64 解密
*
* @param key
* @return
* @throws Exception
*/
public static byte [] BASE64Decrypt(String data)
{
byte [] edata = null ;
try
{
edata = ( new BASE64Decoder()).decodeBuffer(data);
}
catch (Exception e)
{
e.printStackTrace();
}
return edata;
}
/**
* 把 16 位凑成 24 位数组。
*
* @param okey
* @return
*/
private static byte [] convert16To24(byte [] okey)
{
byte [] dkey = new byte [24];
for (int i = 0; i < dkey. length ; i++)
{
dkey[i] = okey[i % 16];
}
return dkey;
}