Des Java source code

* Copyright: Guangzhou dianxun Technology Co., Ltd. 2003

* Created on 2004-2-24 by liudong

*/

Import java. Security .*;

Import javax. crypto. cipher;

Import javax. crypto. secretkey;

Import javax. crypto. secretkeyfactory;

Import javax. crypto. spec. deskeyspec;

/**

* String tool set

* @ Author liudong

*/

Public class stringutils {

Private Static final string password_crypt_key = "_ jdlog _";

Private Final Static string des = "des ";

/**

* Encryption

* @ Param SRC Data Source

* @ Param key, which must be a multiple of 8

* @ Return returns encrypted data.

* @ Throws exception

*/

Public static byte [] encrypt (byte [] SRC, byte [] Key) throws exception {

// The DES algorithm requires a trusted random number Source

Securerandom sr = new securerandom ();

// Create an eyspec object from the original key data

Deskeyspec DKS = new deskeyspec (key );

// Create a key factory and use it to convert the keyspec

// A secretkey object

Secretkeyfactory keyfactory = secretkeyfactory. getinstance (DES );

Secretkey securekey = keyfactory. generatesecret (DKS );

// The cipher object actually completes the encryption operation

Cipher cipher = cipher. getinstance (DES );

// Use the key to initialize the cipher object

Cipher. INIT (Cipher. encrypt_mode, securekey, Sr );

// Now, obtain and encrypt the data

// Perform the encryption operation

Return cipher. dofinal (SRC );

}

/**

* Decryption

* @ Param SRC Data Source

* @ Param key, which must be a multiple of 8

* @ Return returns the decrypted raw data.

* @ Throws exception

*/

Public static byte [] decrypt (byte [] SRC, byte [] Key) throws exception {

// The DES algorithm requires a trusted random number Source

Securerandom sr = new securerandom ();

// Create an eyspec object from the original key data

Deskeyspec DKS = new deskeyspec (key );

// Create a key factory and use it to convert the keyspec object

// A secretkey object

Secretkeyfactory keyfactory = secretkeyfactory. getinstance (DES );

Secretkey securekey = keyfactory. generatesecret (DKS );

// The cipher object actually completes the decryption operation

Cipher cipher = cipher. getinstance (DES );

// Use the key to initialize the cipher object

Cipher. INIT (Cipher. decrypt_mode, securekey, Sr );

// Now, obtain and decrypt the data

// Perform the decryption operation.

Return cipher. dofinal (SRC );

}

/**

* Password decryption

* @ Param data

* @ Return

* @ Throws exception

*/

Public final static string decrypt (string data ){

Try {

Return new string (decrypt (hex2byte (data. getbytes ()),

Password_crypt_key.getbytes ()));

} Catch (exception e ){

}

Return NULL;

}

/**

* Password encryption

* @ Param Password

* @ Return

* @ Throws exception

*/

Public final static string encrypt (string password ){

Try {

Return byte2hex (encrypt (password. getbytes (), password_crypt_key.getbytes ()));
} Catch (exception e ){

}

Return NULL;

}

/**

* Two-line conversion string

* @ Param B

* @ Return

*/

Public static string byte2hex (byte [] B ){

String HS = "";

String stmp = "";

For (INT n = 0; n <B. length; n ++ ){

Stmp = (Java. Lang. Integer. tohexstring (B [N] & 0xff ));

If (stmp. Length () = 1)

HS = HS + "0" + stmp;

Else

HS = HS + stmp;

}

Return HS. touppercase ();

}

Public static byte [] hex2byte (byte [] B ){

If (B. Length % 2 )! = 0)

Throw new illegalargumentexception ("the length is not an even number ");

Byte [] b2 = new byte [B. Length/2];

For (INT n = 0; n <B. length; n + = 2 ){

String item = new string (B, n, 2 );

B2 [n/2] = (byte) integer. parseint (item, 16 );

}

Return B2;