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：
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,$w,$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,$round,$Nb);
}
$state = self::subBytes($state,$Nb);
$state = self::shiftRows($state,$Nb);
$state = self::addRoundKey($state,$Nr,$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,$rnd,$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]; // 2a0 + 3a1 + a2 + a3
$s[1][$c] = $a[0] ^ $b[1] ^ $a[2] ^ $b[2] ^ $a[3]; // a0 2a1 + 3a2 + a3
$s[2][$c] = $a[0] ^ $a[1] ^ $b[2] ^ $a[3] ^ $b[3]; // a0 + a1 + 2a2 + 3a3
$s[3][$c] = $a[0] ^ $b[0] ^ $a[1] ^ $a[2] ^ $b[3]; // 3a0 + 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 $rCon = array(
array(0x00,0x00),array(0x01,array(0x02,array(0x04,array(0x08,array(0x10,array(0x20,array(0x40,array(0x80,array(0x1b,array(0x36,0x00) );
}
?>
class AesCtr extends Aes {
/**
- Encrypt a text using AES encryption in Counter mode of operation
- Unicode multi-byte character safe
- @param plaintext source text to be encrypted
- @param password the password to use to generate a key
- @param nBits number of bits to be used in the key (128,192,or 256)
- @param keep keep 1:each not change 0:each change(default)
- @return encrypted text
*/
public static function encrypt($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($key,$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($nonceMs,$i8) & 0xff;
for ($i=0; $i<2; $i++) $counterBlock[$i+2] = self::urs($nonceRnd,$i8) & 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($b,$c8) & 0xff;
for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs($b/0x100000000,$c8);
$cipherCntr = Aes::cipher($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 $ciphertext;
}
/**
- Decrypt a text encrypted by AES in counter mode of operation
- @param ciphertext source text to be decrypted
- @param password the password to use to generate a key
- @param nBits number of bits to be used in the key (128,or 256)
- @return decrypted text
*/
public static function decrypt($ciphertext,$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($password,$nBytes-16)); // expand key to 16/24/32 bytes long
// recover nonce from 1st element of ciphertext
$counterBlock = array();
$ctrTxt = substr($ciphertext,8);
for ($i=0; $i<8; $i++) $counterBlock[$i] = ord(substr($ctrTxt,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($b,$c8) & 0xff;
for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs(($b+1)/0x100000000-1,$c8) & 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],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：
echo 'each change
';
$mstr = AesCtr::encrypt('Hello World','key',256);
echo "Encrypt String : $mstr
";
$dstr = AesCtr::decrypt($mstr,256);
echo "Decrypt String : $dstr
";
echo 'each not change
';
$mstr = AesCtr::encrypt('Hello World',256,1); // keep=1
echo "Encrypt String : $mstr
";
$dstr = AesCtr::decrypt($mstr,256);
echo "Decrypt String : $dstr
";
?>
$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
";
$dstr = aes($ostr,'decrypt');
echo "String 2: $dstr
";
希望本文所述对大家PHP程序设计的学习有所帮助。
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