PHP symmetric Cryptographic algorithm Example _php tutorial

PHP Symmetric encryption algorithm

KEY is a previously defined constant
Copy the Code code as follows:
Mcrypt::encrypt ();
Mcrypt::d ecrypt ();

Copy the Code code as follows:
Defined (' ROOT ') or exit (' Access Denied ');

Class mcrypt{

public static function Encrypt ($code) {
Return Base64_encode (Mcrypt_encrypt (mcrypt_rijndael_256, MD5 (KEY), $code, MCRYPT_MODE_ECB, Mcrypt_create_iv (mcrypt_ Get_iv_size (mcrypt_rijndael_256, MCRYPT_MODE_ECB), Mcrypt_rand));
}

public static function decrypt ($code) {
Return Mcrypt_decrypt (mcrypt_rijndael_256, MD5 (KEY), Base64_decode ($code), MCRYPT_MODE_ECB, Mcrypt_create_iv (mcrypt _get_iv_size (mcrypt_rijndael_256, MCRYPT_MODE_ECB), Mcrypt_rand));
}

}

Common symmetric encryption Algorithm (DES/AES) class

xcrypt.php
Copy CodeThe code is as follows:
/**
* Common symmetric encryption algorithm classes
* Support key: 64/128/256 bit (byte length 8/16/32)
* Support algorithm: Des/aes (based on key length automatic matching using: Des:64bit aes:128/256bit)
* Support mode: CBC/ECB/OFB/CFB
* Ciphertext Code: Base64 string/16 binary string/binary string stream
* Fill mode: pkcs5padding (DES)
*
* @author: Linvo
* @version: 1.0.0
* @date: 2013/1/10
*/
Class xcrypt{

Private $mcrypt;
Private $key;
Private $mode;
Private $iv;
Private $blocksize;

/**
* Constructor function
*
* @param string key
* @param string mode
* @param string vector ("off": Not used/"Auto": Auto/Other: Specify value, length with key)
*/
Public function __construct ($key, $mode = ' CBC ', $iv = "Off") {
Switch (strlen ($key)) {
Case 8:
$this->mcrypt = mcrypt_des;
Break
Case 16:
$this->mcrypt = mcrypt_rijndael_128;
Break
Case 32:
$this->mcrypt = mcrypt_rijndael_256;
Break
Default
Die ("Key size must is 8/16/32");
}

$this->key = $key;

Switch (Strtolower ($mode)) {
Case ' OFB ':
$this->mode = MCRYPT_MODE_OFB;
if ($iv = = ' off ') die (' OFB must give a IV '); OFB must have a vector
Break
Case ' CFB ':
$this->mode = MCRYPT_MODE_CFB;
if ($iv = = ' off ') die (' CFB must give a IV '); The CFB must have a vector
Break
Case ' ECB ':
$this->mode = MCRYPT_MODE_ECB;
$iv = ' off '; The ECB does not need vectors
Break
Case ' CBC ':
Default
$this->mode = MCRYPT_MODE_CBC;
}

Switch (Strtolower ($IV)) {
Case "Off":
$this->iv = null;
Break
Case "Auto":
$source = php_os== ' WINNT '? Mcrypt_rand:mcrypt_dev_random;
$this->iv = Mcrypt_create_iv (Mcrypt_get_block_size ($this->mcrypt, $this->mode), $source);
Break
Default
$this->iv = $iv;
}


}


/**
* Get vector values
* @param string vector value encoding (base64/hex/bin)
* @return String vector value
*/
Public Function Getiv ($code = ' base64 ') {
Switch ($code) {
Case ' base64 ':
$ret = Base64_encode ($this->iv);
Break
Case ' hex ':
$ret = Bin2Hex ($this->iv);
Break
Case ' bin ':
Default
$ret = $this->iv;
}
return $ret;
}


/**
* Encryption
* @param string plaintext
* @param string cipher encoding (Base64/hex/bin)
* @return String cipher
*/
Public function Encrypt ($str, $code = ' base64 ') {
if ($this->mcrypt = = mcrypt_des) $str = $this->_pkcs5pad ($STR);

if (Isset ($this->iv)) {
$result = Mcrypt_encrypt ($this->mcrypt, $this->key, $str, $this->mode, $this->iv);
} else {
@ $result = Mcrypt_encrypt ($this->mcrypt, $this->key, $str, $this->mode);
}

Switch ($code) {
Case ' base64 ':
$ret = Base64_encode ($result);
Break
Case ' hex ':
$ret = Bin2Hex ($result);
Break
Case ' bin ':
Default
$ret = $result;
}

return $ret;

}

/**
* Decryption
* @param string cipher
* @param string cipher encoding (Base64/hex/bin)
* @return String plaintext
*/
Public function Decrypt ($str, $code = "base64") {
$ret = false;

Switch ($code) {
Case ' base64 ':
$str = Base64_decode ($STR);
Break
Case ' hex ':
$str = $this->_hex2bin ($STR);
Break
Case ' bin ':
Default
}

if ($str!== false) {
if (Isset ($this->iv)) {
$ret = Mcrypt_decrypt ($this->mcrypt, $this->key, $str, $this->mode, $this->iv);
} else {
@ $ret = Mcrypt_decrypt ($this->mcrypt, $this->key, $str, $this->mode);
}
if ($this->mcrypt = = mcrypt_des) $ret = $this->_pkcs5unpad ($ret);
$ret = Trim ($ret);
}

return $ret;
}

Private Function _pkcs5pad ($text) {
$this->blocksize = mcrypt_get_block_size ($this->mcrypt, $this->mode);
$pad = $this->blocksize-(strlen ($text)% $this->blocksize);
Return $text. Str_repeat (Chr ($pad), $pad);
}

Private Function _pkcs5unpad ($text) {
$pad = Ord ($text {strlen ($text)-1});
if ($pad > strlen ($text)) return false;
if (strspn ($text, Chr ($pad), strlen ($text)-$pad)! = $pad) return false;
$ret = substr ($text, 0,-1 * $pad);
return $ret;
}

Private Function _hex2bin ($hex = False) {
$ret = $hex!== false && preg_match ('/^[0-9a-fa-f]+$/i ', $hex)? Pack ("h*", $hex): false;
return $ret;
}
}

How to use the above class

Copy the Code code as follows:
Header (' content-type:text/html; Charset=utf-8; ');

Include "xcrypt.php";

Echo '

';    
$a = isset ($_get[' a ')? $_get[' A ']: ' Test 123 ';  

Secret key  
$key = ' 12345678123456781234567812345678 '; Bit  
$key = ' 1234567812345678 '; -bit  
$key = ' 12345678 '; A bit  

Setup mode and IV  
$m = new Xcrypt ($key, ' CBC ', ' Auto ');  

Get vector value  
echo ' vector: ';  
Var_dump ($m->getiv ());  

Encryption  
$b = $m->encrypt ($a, ' base64 ');  
Decrypt  
$c = $m->decrypt ($b, ' base64 ');  

Echo ' after encryption: ';  
Var_dump ($b);  
Echo ' decryption: ';  
Var_dump ($c);  
Echo '

';

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