PHP教程：TEA算法实现

算法简单,而且效率高,每次可以操作8个字节的数据,加密解密的KEY为16字节,即包含4个int数据的int型数组,加密轮数应为8的倍数,一般比较常用的轮数为64,32,16,QQ原来就是用TEA16来还原密码的.

TEA算法
核心为：

#include

void encrypt (uint32_t* v, uint32_t* k) {
    uint32_t v0=v[0], v1=v[1], sum=0, i;           /* set up */
    uint32_t delta=0x9e3779b9;                     /* a key schedule constant */
    uint32_t k0=k[0], k1=k[1], k2=k[2], k3=k[3];   /* cache key */
    for (i=0; i         sum += delta;
        v0 += ((v1>5) + k1);
        v1 += ((v0>5) + k3); 
    }                                              /* end cycle */
    v[0]=v0; v[1]=v1;
}

void decrypt (uint32_t* v, uint32_t* k) {
    uint32_t v0=v[0], v1=v[1], sum=0xC6EF3720, i;  /* set up */
    uint32_t delta=0x9e3779b9;                     /* a key schedule constant */
    uint32_t k0=k[0], k1=k[1], k2=k[2], k3=k[3];   /* cache key */
    for (i=0; i         v1 -= ((v0>5) + k3);
        v0 -= ((v1>5) + k1);
        sum -= delta;                                  
    }                                              /* end cycle */
    v[0]=v0; v[1]=v1;
}

PHP部分代码非我原创，大家可以了解一下这方面的知识

$date = '8345354023476-3434';
$key = '12345';
$t = new tea ( );
$tea = $t->encrypt ( $date, $key );
$eetea = $t->decrypt ( $tea, $key );
var_dump ( $tea );
var_dump ( $eetea );
class tea {
    private $a, $b, $c, $d;
    private $n_iter;
    public function __construct() {
        $this->setIter ( 32 );
    }
    private function setIter($n_iter) {
        $this->n_iter = $n_iter;
    }
    private function getIter() {
        return $this->n_iter;
    }
    public function encrypt($data, $key) {
        // resize data to 32 bits (4 bytes)
        $n = $this->_resize ( $data, 4 );
       
        // convert data to long
        $data_long [0] = $n;
        $n_data_long = $this->_str2long ( 1, $data, $data_long );
       
        // resize data_long to 64 bits (2 longs of 32 bits)
        $n = count ( $data_long );
        if (($n & 1) == 1) {
            $data_long [$n] = chr ( 0 );
            $n_data_long ++;
        }
       
        // resize key to a multiple of 128 bits (16 bytes)
        $this->_resize ( $key, 16, true );
        if ('' == $key)
            $key = '0000000000000000';
           
        // convert key to long
        $n_key_long = $this->_str2long ( 0, $key, $key_long );
       
        // encrypt the long data with the key
        $enc_data = '';
        $w = array (0, 0 );
        $j = 0;
        $k = array (0, 0, 0, 0 );
        for($i = 0; $i             // get next key part of 128 bits
            if ($j + 4                 $k [0] = $key_long [$j];
                $k [1] = $key_long [$j + 1];
                $k [2] = $key_long [$j + 2];
                $k [3] = $key_long [$j + 3];
            } else {
                $k [0] = $key_long [$j % $n_key_long];
                $k [1] = $key_long [($j + 1) % $n_key_long];
                $k [2] = $key_long [($j + 2) % $n_key_long];
                $k [3] = $key_long [($j + 3) % $n_key_long];
            }
            $j = ($j + 4) % $n_key_long;
           
            $this->_encipherLong ( $data_long [$i], $data_long [++ $i], $w, $k );
           
            // append the enciphered longs to the result
            $enc_data .= $this->_long2str ( $w [0] );
            $enc_data .= $this->_long2str ( $w [1] );
        }
       
        return $enc_data;
    }
    public function decrypt($enc_data, $key) {
        // convert data to long
        $n_enc_data_long = $this->_str2long ( 0, $enc_data, $enc_data_long );
       
        // resize key to a multiple of 128 bits (16 bytes)
        $this->_resize ( $key, 16, true );
        if ('' == $key)
            $key = '0000000000000000';
           
        // convert key to long
        $n_key_long = $this->_str2long ( 0, $key, $key_long );
       
        // decrypt the long data with the key
        $data = '';
        $w = array (0, 0 );
        $j = 0;
        $len = 0;
        $k = array (0, 0, 0, 0 );
        $pos = 0;
       
        for($i = 0; $i             // get next key part of 128 bits
            if ($j + 4                 $k [0] = $key_long [$j];
                $k [1] = $key_long [$j + 1];
                $k [2] = $key_long [$j + 2];
                $k [3] = $key_long [$j + 3];
            } else {
                $k [0] = $key_long [$j % $n_key_long];
                $k [1] = $key_long [($j + 1) % $n_key_long];
                $k [2] = $key_long [($j + 2) % $n_key_long];
                $k [3] = $key_long [($j + 3) % $n_key_long];
            }
            $j = ($j + 4) % $n_key_long;
           
            $this->_decipherLong ( $enc_data_long [$i], $enc_data_long [$i + 1], $w, $k );
           
            // append the deciphered longs to the result data (remove padding)
            if (0 == $i) {
                $len = $w [0];
                if (4                     $data .= $this->_long2str ( $w [1] );
                } else {
                    $data .= substr ( $this->_long2str ( $w [1] ), 0, $len % 4 );
                }
            } else {
                $pos = ($i - 1) * 4;
                if ($pos + 4                     $data .= $this->_long2str ( $w [0] );
                   
                    if ($pos + 8                         $data .= $this->_long2str ( $w [1] );
                    } elseif ($pos + 4                         $data .= substr ( $this->_long2str ( $w [1] ), 0, $len % 4 );
                    }
                } else {
                    $data .= substr ( $this->_long2str ( $w [0] ), 0, $len % 4 );
                }
            }
        }
        return $data;
    }
    private function _encipherLong($y, $z, &$w, &$k) {
        $sum = ( integer ) 0;
        $delta = 0x9E3779B9;
        $n = ( integer ) $this->n_iter;
       
        while ( $n -- > 0 ) {
                       //C v0 += ((v1>5) + k1);
                       //C v1 += ((v0>5) + k3); 
            $sum = $this->_add ( $sum, $delta );
            $y = $this->_add ( $y, $this->_add ( ($z a) ^ $this->_add($z , $sum) ^ $this->_add($this->_rshift ( $z, 5 ), $this->b )  );
            $z = $this->_add ( $z, $this->_add ( ($y a) ^ $this->_add($y , $sum) ^ $this->_add($this->_rshift ( $y, 5 ), $this->b )  );
        }
       
        $w [0] = $y;
        $w [1] = $z;
    }
    private function _decipherLong($y, $z, &$w, &$k) {
        // sum = delta         $sum = 0xC6EF3720;
        $delta = 0x9E3779B9;
        $n = ( integer ) $this->n_iter;
       
        while ( $n -- > 0 ) {
                    //C v1 -= ((v0>5) + k3);
                    //C v0 -= ((v1>5) + k1);
            $z = $this->_add ( $z, -($this->_add ( ($y a) ^ $this->_add($y , $sum) ^ $this->_add($this->_rshift ( $y, 5 ), $this->b ) ) );
            $y = $this->_add ( $y, - ($this->_add ( ($z a) ^ $this->_add($z , $sum) ^ $this->_add($this->_rshift ( $z, 5 ), $this->b ) ) );
            $sum = $this->_add ( $sum, - $delta );
            }
       
        $w [0] = $y;
        $w [1] = $z;
    }
    private function _resize(&$data, $size, $nonull = false) {
        $n = strlen ( $data );
        $nmod = $n % $size;
        if (0 == $nmod)
            $nmod = $size;
       
        if ($nmod > 0) {
            if ($nonull) {
                for($i = $n; $i                     $data [$i] = $data [$i % $n];
                }
            } else {
                for($i = $n; $i                     $data [$i] = chr ( 0 );
                }
            }
        }
        return $n;
    }
    private function _hex2bin($str) {
        $len = strlen ( $str );
        return pack ( 'H' . $len, $str );
    }
    private function _str2long($start, &$data, &$data_long) {
        $n = strlen ( $data );
       
        $tmp = unpack ( 'N*', $data );
        $j = $start;
       
        foreach ( $tmp as $value )
            $data_long [$j ++] = $value;
       
        return $j;
    }
    private function _long2str($l) {
        return pack ( 'N', $l );
    }
   
   
    private function _rshift($integer, $n) {
        // convert to 32 bits
        if (0xffffffff $integer) {
            $integer = fmod ( $integer, 0xffffffff + 1 );
        }
       
        // convert to unsigned integer
        if (0x7fffffff             $integer -= 0xffffffff + 1.0;
        } elseif (- 0x80000000 > $integer) {
            $integer += 0xffffffff + 1.0;
        }
       
        // do right shift
        if (0 > $integer) {
            $integer &= 0x7fffffff; // remove sign bit before shift
            $integer >>= $n; // right shift
            $integer = 1         } else {
            $integer >>= $n; // use normal right shift
        }
       
        return $integer;
    }
    private function _add($i1, $i2) {
        $result = 0.0;
       
        foreach ( func_get_args () as $value ) {
            // remove sign if necessary
            if (0.0 > $value) {
                $value -= 1.0 + 0xffffffff;
            }
           
            $result += $value;
        }
       
        // convert to 32 bits
        if (0xffffffff $result) {
            $result = fmod ( $result, 0xffffffff + 1 );
        }
       
        // convert to signed integer
        if (0x7fffffff             $result -= 0xffffffff + 1.0;
        } elseif (- 0x80000000 > $result) {
            $result += 0xffffffff + 1.0;
        }
       
        return $result;
    }
   
// }}}
}
?>

上面的是TEA的算法，XTEA的算法为：
 

#include

void encipher(unsigned int num_rounds, uint32_t v[2], uint32_t const k[4]) {
    unsigned int i;
    uint32_t v0=v[0], v1=v[1], sum=0, delta=0x9E3779B9;
    for (i=0; i         v0 += (((v1 > 5)) + v1) ^ (sum + k[sum & 3]);
        sum += delta;
        v1 += (((v0 > 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
    }
    v[0]=v0; v[1]=v1;
}

void decipher(unsigned int num_rounds, uint32_t v[2], uint32_t const k[4]) {
    unsigned int i;
    uint32_t v0=v[0], v1=v[1], delta=0x9E3779B9, sum=delta*num_rounds;
    for (i=0; i         v1 −= (((v0 > 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
        sum −= delta;
        v0 −= (((v1 > 5)) + v1) ^ (sum + k[sum & 3]);
    }
    v[0]=v0; v[1]=v1;
}

那PHP中只需要把运算的位置改下就OK
 

    private function _teaencipherLong($y, $z, &$w, &$k) {
        $sum = ( integer ) 0;
        $delta = 0x9E3779B9;
        $n = ( integer ) $this->n_iter;
       
        while ( $n -- > 0 ) {
            $y = $this->_add ( $y, $this->_add ( $z _rshift ( $z, 5 ), $z ) ^ $this->_add ( $sum, $k [$sum & 3] ) );
            $sum = $this->_add ( $sum, $delta );
            $z = $this->_add ( $z, $this->_add ( $y _rshift ( $y, 5 ), $y ) ^ $this->_add ( $sum, $k [$this->_rshift ( $sum, 11 ) & 3] ) );
        }
       
        $w [0] = $y;
        $w [1] = $z;
    }   
    private function _decipherLong($y, $z, &$w, &$k) {
        // sum = delta         $sum = 0xC6EF3720;
        $delta = 0x9E3779B9;
        $n = ( integer ) $this->n_iter;
       
        while ( $n -- > 0 ) {
            $z = $this->_add ( $z, - ($this->_add ( $y _rshift ( $y, 5 ), $y ) ^ $this->_add ( $sum, $k [$this->_rshift ( $sum, 11 ) & 3] )) );
            $sum = $this->_add ( $sum, - $delta );
            $y = $this->_add ( $y, - ($this->_add ( $z _rshift ( $z, 5 ), $z ) ^ $this->_add ( $sum, $k [$sum & 3] )) );
        }
       
        $w [0] = $y;
        $w [1] = $z;
    }

XXTEA的算法
核心为
 

#define MX (z>>5^y>3^z

  long btea(long* v, long n, long* k) {
    unsigned long z=v[n-1], y=v[0], sum=0, e, DELTA=0x9e3779b9;
    long p, q ;
    if (n > 1) {          /* Coding Part */
      q = 6 + 52/n;
      while (q-- > 0) {
        sum += DELTA;
        e = (sum >> 2) & 3;
        for (p=0; p         y = v[0];
        z = v[n-1] += MX;
      }
      return 0 ;
    } else if (n       n = -n;
      q = 6 + 52/n;
      sum = q*DELTA ;
      while (sum != 0) {
        e = (sum >> 2) & 3;
        for (p=n-1; p>0; p--) z = v[p-1], y = v[p] -= MX;
        z = v[n-1];
        y = v[0] -= MX;
        sum -= DELTA;
      }
      return 0;
    }
    return 1;
  }

也是运算不一样，这个就不写了，有人已经写过这方面的代码了