本文实例讲述了PHP实现AES256加密算法的方法，是较为常见的一种加密算法。分享给大家供大家参考。具体如下：

aes.class.php文件如下：

<?php

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

/* AES implementation in PHP (c) Chris Veness 2005-2011. Right of free use is granted for all */

/* commercial or non-commercial use under CC-BY licence. No warranty of any form is offered. */

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

class Aes {

/**

* AES Cipher function: encrypt 'input' with Rijndael algorithm

*

* @param input message as byte-array (16 bytes)

* @param w key schedule as 2D byte-array (Nr+1 x Nb bytes) -

* generated from the cipher key by keyExpansion()

* @return ciphertext as byte-array (16 bytes)

*/

public static function cipher($input, $w) { // main cipher function [§5.1]

$Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES)

$Nr = count($w)/$Nb - 1; // no of rounds: 10/12/14 for 128/192/256-bit keys

$state = array(); // initialise 4xNb byte-array 'state' with input [§3.4]

for ($i=0; $i<4*$Nb; $i++) $state[$i%4][floor($i/4)] = $input[$i];

$state = self::addRoundKey($state, $w, 0, $Nb);

for ($round=1; $round<$Nr; $round++) { // apply Nr rounds

$state = self::subBytes($state, $Nb);

$state = self::shiftRows($state, $Nb);

$state = self::mixColumns($state, $Nb);

$state = self::addRoundKey($state, $w, $round, $Nb);

}

$state = self::subBytes($state, $Nb);

$state = self::shiftRows($state, $Nb);

$state = self::addRoundKey($state, $w, $Nr, $Nb);

$output = array(4*$Nb); // convert state to 1-d array before returning [§3.4]

for ($i=0; $i<4*$Nb; $i++) $output[$i] = $state[$i%4][floor($i/4)];

return $output;

}

private static function addRoundKey($state, $w, $rnd, $Nb) { // xor Round Key into state S [§5.1.4]

for ($r=0; $r<4; $r++) {

for ($c=0; $c<$Nb; $c++) $state[$r][$c] ^= $w[$rnd*4+$c][$r];

}

return $state;

}

private static function subBytes($s, $Nb) { // apply SBox to state S [§5.1.1]

for ($r=0; $r<4; $r++) {

for ($c=0; $c<$Nb; $c++) $s[$r][$c] = self::$sBox[$s[$r][$c]];

}

return $s;

}

private static function shiftRows($s, $Nb) { // shift row r of state S left by r bytes [§5.1.2]

$t = array(4);

for ($r=1; $r<4; $r++) {

for ($c=0; $c<4; $c++) $t[$c] = $s[$r][($c+$r)%$Nb]; // shift into temp copy

for ($c=0; $c<4; $c++) $s[$r][$c] = $t[$c]; // and copy back

} // note that this will work for Nb=4,5,6, but not 7,8 (always 4 for AES):

return $s; // see fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.311.pdf

}

private static function mixColumns($s, $Nb) { // combine bytes of each col of state S [§5.1.3]

for ($c=0; $c<4; $c++) {

$a = array(4); // 'a' is a copy of the current column from 's'

$b = array(4); // 'b' is a•{02} in GF(2^8)

for ($i=0; $i<4; $i++) {

$a[$i] = $s[$i][$c];

$b[$i] = $s[$i][$c]&0x80 ? $s[$i][$c]<<1 ^ 0x011b : $s[$i][$c]<<1;

}

// a[n] ^ b[n] is a•{03} in GF(2^8)

$s[0][$c] = $b[0] ^ $a[1] ^ $b[1] ^ $a[2] ^ $a[3]; // 2*a0 + 3*a1 + a2 + a3

$s[1][$c] = $a[0] ^ $b[1] ^ $a[2] ^ $b[2] ^ $a[3]; // a0 * 2*a1 + 3*a2 + a3

$s[2][$c] = $a[0] ^ $a[1] ^ $b[2] ^ $a[3] ^ $b[3]; // a0 + a1 + 2*a2 + 3*a3

$s[3][$c] = $a[0] ^ $b[0] ^ $a[1] ^ $a[2] ^ $b[3]; // 3*a0 + a1 + a2 + 2*a3

}

return $s;

}

/**

* Key expansion for Rijndael cipher(): performs key expansion on cipher key

* to generate a key schedule

*

* @param key cipher key byte-array (16 bytes)

* @return key schedule as 2D byte-array (Nr+1 x Nb bytes)

*/

public static function keyExpansion($key) { // generate Key Schedule from Cipher Key [§5.2]

$Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES)

$Nk = count($key)/4; // key length (in words): 4/6/8 for 128/192/256-bit keys

$Nr = $Nk + 6; // no of rounds: 10/12/14 for 128/192/256-bit keys

$w = array();

$temp = array();

for ($i=0; $i<$Nk; $i++) {

$r = array($key[4*$i], $key[4*$i+1], $key[4*$i+2], $key[4*$i+3]);

$w[$i] = $r;

}

for ($i=$Nk; $i<($Nb*($Nr+1)); $i++) {

$w[$i] = array();

for ($t=0; $t<4; $t++) $temp[$t] = $w[$i-1][$t];

if ($i % $Nk == 0) {

$temp = self::subWord(self::rotWord($temp));

for ($t=0; $t<4; $t++) $temp[$t] ^= self::$rCon[$i/$Nk][$t];

} else if ($Nk > 6 && $i%$Nk == 4) {

$temp = self::subWord($temp);

}

for ($t=0; $t<4; $t++) $w[$i][$t] = $w[$i-$Nk][$t] ^ $temp[$t];

}

return $w;

}

private static function subWord($w) { // apply SBox to 4-byte word w

for ($i=0; $i<4; $i++) $w[$i] = self::$sBox[$w[$i]];

return $w;

}

private static function rotWord($w) { // rotate 4-byte word w left by one byte

$tmp = $w[0];

for ($i=0; $i<3; $i++) $w[$i] = $w[$i+1];

$w[3] = $tmp;

return $w;

}

// sBox is pre-computed multiplicative inverse in GF(2^8) used in subBytes and keyExpansion [§5.1.1]

private static $sBox = array(

0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76,

0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0,

0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15,

0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75,

0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84,

0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf,

0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8,

0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2,

0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73,

0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb,

0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79,

0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08,

0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a,

0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e,

0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf,

0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16);

// rCon is Round Constant used for the Key Expansion [1st col is 2^(r-1) in GF(2^8)] [§5.2]

private static $rCon = array(

array(0x00, 0x00, 0x00, 0x00),

array(0x01, 0x00, 0x00, 0x00),

array(0x02, 0x00, 0x00, 0x00),

array(0x04, 0x00, 0x00, 0x00),

array(0x08, 0x00, 0x00, 0x00),

array(0x10, 0x00, 0x00, 0x00),

array(0x20, 0x00, 0x00, 0x00),

array(0x40, 0x00, 0x00, 0x00),

array(0x80, 0x00, 0x00, 0x00),

array(0x1b, 0x00, 0x00, 0x00),

array(0x36, 0x00, 0x00, 0x00) );

}

?>

aesctr.class.php文件如下：

<?php

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

/* AES counter (CTR) mode implementation in PHP (c) Chris Veness 2005-2011. Right of free use is */

/* granted for all commercial or non-commercial use under CC-BY licence. No warranty of any */

/* form is offered. */

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

class AesCtr extends Aes {

/**

* Encrypt a text using AES encryption in Counter mode of operation

* - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

*

* Unicode multi-byte character safe

*

* @param plaintext source text to be encrypted

* @param password the password to use to generate a key

* @param nBits number of bits to be used in the key (128, 192, or 256)

* @param keep keep 1:each not change 0:each change(default)

* @return encrypted text

*/

public static function encrypt($plaintext, $password, $nBits, $keep=0) {

$blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES

if (!($nBits==128 || $nBits==192 || $nBits==256)) return ''; // standard allows 128/192/256 bit keys

// note PHP (5) gives us plaintext and password in UTF8 encoding!

// use AES itself to encrypt password to get cipher key (using plain password as source for

// key expansion) - gives us well encrypted key

$nBytes = $nBits/8; // no bytes in key

$pwBytes = array();

for ($i=0; $i<$nBytes; $i++) $pwBytes[$i] = ord(substr($password,$i,1)) & 0xff;

$key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));

$key = array_merge($key, array_slice($key, 0, $nBytes-16)); // expand key to 16/24/32 bytes long

// initialise 1st 8 bytes of counter block with nonce (NIST SP800-38A §B.2): [0-1] = millisec,

// [2-3] = random, [4-7] = seconds, giving guaranteed sub-ms uniqueness up to Feb 2106

$counterBlock = array();

if($keep==0){

$nonce = floor(microtime(true)*1000); // timestamp: milliseconds since 1-Jan-1970

$nonceMs = $nonce%1000;

$nonceSec = floor($nonce/1000);

$nonceRnd = floor(rand(0, 0xffff));

}else{

$nonce = 10000;

$nonceMs = $nonce%1000;

$nonceSec = floor($nonce/1000);

$nonceRnd = 10000;

}

for ($i=0; $i<2; $i++) $counterBlock[$i] = self::urs($nonceMs, $i*8) & 0xff;

for ($i=0; $i<2; $i++) $counterBlock[$i+2] = self::urs($nonceRnd, $i*8) & 0xff;

for ($i=0; $i<4; $i++) $counterBlock[$i+4] = self::urs($nonceSec, $i*8) & 0xff;

// and convert it to a string to go on the front of the ciphertext

$ctrTxt = '';

for ($i=0; $i<8; $i++) $ctrTxt .= chr($counterBlock[$i]);

// generate key schedule - an expansion of the key into distinct Key Rounds for each round

$keySchedule = Aes::keyExpansion($key);

//print_r($keySchedule);

$blockCount = ceil(strlen($plaintext)/$blockSize);

$ciphertxt = array(); // ciphertext as array of strings

for ($b=0; $b<$blockCount; $b++) {

// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)

// done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)

for ($c=0; $c<4; $c++) $counterBlock[15-$c] = self::urs($b, $c*8) & 0xff;

for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs($b/0x100000000, $c*8);

$cipherCntr = Aes::cipher($counterBlock, $keySchedule); // -- encrypt counter block --

// block size is reduced on final block

$blockLength = $b<$blockCount-1 ? $blockSize : (strlen($plaintext)-1)%$blockSize+1;

$cipherByte = array();

for ($i=0; $i<$blockLength; $i++) { // -- xor plaintext with ciphered counter byte-by-byte --

$cipherByte[$i] = $cipherCntr[$i] ^ ord(substr($plaintext, $b*$blockSize+$i, 1));

$cipherByte[$i] = chr($cipherByte[$i]);

}

$ciphertxt[$b] = implode('', $cipherByte); // escape troublesome characters in ciphertext

}

// implode is more efficient than repeated string concatenation

$ciphertext = $ctrTxt . implode('', $ciphertxt);

$ciphertext = base64_encode($ciphertext);

return $ciphertext;

}

/**

* Decrypt a text encrypted by AES in counter mode of operation

*

* @param ciphertext source text to be decrypted

* @param password the password to use to generate a key

* @param nBits number of bits to be used in the key (128, 192, or 256)

* @return decrypted text

*/

public static function decrypt($ciphertext, $password, $nBits) {

$blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES

if (!($nBits==128 || $nBits==192 || $nBits==256)) return ''; // standard allows 128/192/256 bit keys

$ciphertext = base64_decode($ciphertext);

// use AES to encrypt password (mirroring encrypt routine)

$nBytes = $nBits/8; // no bytes in key

$pwBytes = array();

for ($i=0; $i<$nBytes; $i++) $pwBytes[$i] = ord(substr($password,$i,1)) & 0xff;

$key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));

$key = array_merge($key, array_slice($key, 0, $nBytes-16)); // expand key to 16/24/32 bytes long

// recover nonce from 1st element of ciphertext

$counterBlock = array();

$ctrTxt = substr($ciphertext, 0, 8);

for ($i=0; $i<8; $i++) $counterBlock[$i] = ord(substr($ctrTxt,$i,1));

// generate key schedule

$keySchedule = Aes::keyExpansion($key);

// separate ciphertext into blocks (skipping past initial 8 bytes)

$nBlocks = ceil((strlen($ciphertext)-8) / $blockSize);

$ct = array();

for ($b=0; $b<$nBlocks; $b++) $ct[$b] = substr($ciphertext, 8+$b*$blockSize, 16);

$ciphertext = $ct; // ciphertext is now array of block-length strings

// plaintext will get generated block-by-block into array of block-length strings

$plaintxt = array();

for ($b=0; $b<$nBlocks; $b++) {

// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)

for ($c=0; $c<4; $c++) $counterBlock[15-$c] = self::urs($b, $c*8) & 0xff;

for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs(($b+1)/0x100000000-1, $c*8) & 0xff;

$cipherCntr = Aes::cipher($counterBlock, $keySchedule); // encrypt counter block

$plaintxtByte = array();

for ($i=0; $i<strlen($ciphertext[$b]); $i++) {

// -- xor plaintext with ciphered counter byte-by-byte --

$plaintxtByte[$i] = $cipherCntr[$i] ^ ord(substr($ciphertext[$b],$i,1));

$plaintxtByte[$i] = chr($plaintxtByte[$i]);

}

$plaintxt[$b] = implode('', $plaintxtByte);

}

// join array of blocks into single plaintext string

$plaintext = implode('',$plaintxt);

return $plaintext;

}

/*

* Unsigned right shift function, since PHP has neither >>> operator nor unsigned ints

*

* @param a number to be shifted (32-bit integer)

* @param b number of bits to shift a to the right (0..31)

* @return a right-shifted and zero-filled by b bits

*/

private static function urs($a, $b) {

$a &= 0xffffffff; $b &= 0x1f; // (bounds check)

if ($a&0x80000000 && $b>0) { // if left-most bit set

$a = ($a>>1) & 0x7fffffff; // right-shift one bit & clear left-most bit

$a = $a >> ($b-1); // remaining right-shifts

} else { // otherwise

$a = ($a>>$b); // use normal right-shift

}

return $a;

}

}

?>

Demo实例程序如下：

<?php

require 'aes.class.php'; // AES PHP implementation

require 'aesctr.class.php'; // AES Counter Mode implementation

echo 'each change<br>';

$mstr = AesCtr::encrypt('Hello World', 'key', 256);

echo "Encrypt String : $mstr<br />";

$dstr = AesCtr::decrypt($mstr, 'key', 256);

echo "Decrypt String : $dstr<br />";

echo 'each not change<br>';

$mstr = AesCtr::encrypt('Hello World', 'key', 256, 1); // keep=1

echo "Encrypt String : $mstr<br />";

$dstr = AesCtr::decrypt($mstr, 'key', 256);

echo "Decrypt String : $dstr<br />";

?>

这里再介绍另一使用 PHP mcrypt 加解密方法：

/* aes 256 encrypt

* @param String $ostr

* @param String $securekey

* @param String $type encrypt, decrypt

*/

function aes($ostr, $securekey, $type='encrypt'){

if($ostr==''){

return '';

}

$key = $securekey;

$iv = strrev($securekey);

$td = mcrypt_module_open('rijndael-256', '', 'ofb', '');

mcrypt_generic_init($td, $key, $iv);

$str = '';

switch($type){

case 'encrypt':

$str = base64_encode(mcrypt_generic($td, $ostr));

break;

case 'decrypt':

$str = mdecrypt_generic($td, base64_decode($ostr));

break;

}

mcrypt_generic_deinit($td);

return $str;

}

// Demo

$key = "fdipzone201314showmethemoney!@#$";

$str = "show me the money";

$ostr = aes($str, $key);

echo "String 1: $ostr<br />";

$dstr = aes($ostr, $key, 'decrypt');

echo "String 2: $dstr<br />";

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