算法簡單,而且效率高,每次可以操作8個字節的數據,加密解密的KEY為16字節,即包含4個int數據的int型數組,加密輪數應為8的倍數,一般比較常用的輪數為64,32,16,QQ原來就是用TEA16來還原密碼的.
TEA算法
核心為：
#include <stdint.h>
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 < 32; i++) { /* basic cycle start */
sum += delta;
v0 += ((v1<<4) + k0) ^ (v1 + sum) ^ ((v1>>5) + k1);
v1 += ((v0<<4) + k2) ^ (v0 + sum) ^ ((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<32; i++) { /* basic cycle start */
v1 -= ((v0<<4) + k2) ^ (v0 + sum) ^ ((v0>>5) + k3);
v0 -= ((v1<<4) + k0) ^ (v1 + sum) ^ ((v1>>5) + k1);
sum -= delta;
} /* end cycle */
v[0]=v0; v[1]=v1;
}
PHP部分代碼非我原創，大家可以了解一下這方面的知識
<?php
$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 < $n_data_long; ++ $i) {
// get next key part of 128 bits
if ($j + 4 <= $n_key_long) {
$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 < $n_enc_data_long; $i += 2) {
// get next key part of 128 bits
if ($j + 4 <= $n_key_long) {
$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 <= $len) {
$data .= $this->_long2str ( $w [1] );
} else {
$data .= substr ( $this->_long2str ( $w [1] ), 0, $len % 4 );
}
} else {
$pos = ($i - 1) * 4;
if ($pos + 4 <= $len) {
$data .= $this->_long2str ( $w [0] );
if ($pos + 8 <= $len) {
$data .= $this->_long2str ( $w [1] );
} elseif ($pos + 4 < $len) {
$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<<4) + k0) ^ (v1 + sum) ^ ((v1>>5) + k1);
//C v1 += ((v0<<4) + k2) ^ (v0 + sum) ^ ((v0>>5) + k3);
$sum = $this->_add ( $sum, $delta );
$y = $this->_add ( $y, $this->_add ( ($z << 4),$this->a) ^ $this->_add($z , $sum) ^ $this->_add($this->_rshift ( $z, 5 ), $this->b ) );
$z = $this->_add ( $z, $this->_add ( ($y << 4),$this->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<<5, in general sum = delta * n
$sum = 0xC6EF3720;
$delta = 0x9E3779B9;
$n = ( integer ) $this->n_iter;
while ( $n -- > 0 ) {
//C v1 -= ((v0<<4) + k2) ^ (v0 + sum) ^ ((v0>>5) + k3);
//C v0 -= ((v1<<4) + k0) ^ (v1 + sum) ^ ((v1>>5) + k1);
$z = $this->_add ( $z, -($this->_add ( ($y << 4),$this->a) ^ $this->_add($y , $sum) ^ $this->_add($this->_rshift ( $y, 5 ), $this->b ) ) );
$y = $this->_add ( $y, - ($this->_add ( ($z << 4),$this->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 < $n - $nmod + $size; ++ $i) {
$data [$i] = $data [$i % $n];
}
} else {
for($i = $n; $i < $n - $nmod + $size; ++ $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 || - 0xffffffff > $integer) {
$integer = fmod ( $integer, 0xffffffff + 1 );
}
// convert to unsigned integer
if (0x7fffffff < $integer) {
$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 << (31 - $n); // set shifted sign bit
} 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 || - 0xffffffff > $result) {
$result = fmod ( $result, 0xffffffff + 1 );
}
// convert to signed integer
if (0x7fffffff < $result) {
$result -= 0xffffffff + 1.0;
} elseif (- 0x80000000 > $result) {
$result += 0xffffffff + 1.0;
}
return $result;
}
// }}}
}
?>
上面的是TEA的算法，XTEA的算法為：
那PHP中只需要把運算的位置改下就OK
private function _teaencipherLong($y, $z, &$w, &$k) {
$sum = ( integer ) 0;
$delta = 0x9E3779B9;
$n = ( integer ) $this->n_iter;
while ( $n -- > 0 ) {
$y = $this->_add ( $y, $this->_add ( $z << 4 ^ $this->_rshift ( $z, 5 ), $z ) ^ $this->_add ( $sum, $k [$sum & 3] ) );
$sum = $this->_add ( $sum, $delta );
$z = $this->_add ( $z, $this->_add ( $y << 4 ^ $this->_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<<5, in general sum = delta * n
$sum = 0xC6EF3720;
$delta = 0x9E3779B9;
$n = ( integer ) $this->n_iter;
while ( $n -- > 0 ) {
$z = $this->_add ( $z, - ($this->_add ( $y << 4 ^ $this->_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 << 4 ^ $this->_rshift ( $z, 5 ), $z ) ^ $this->_add ( $sum, $k [$sum & 3] )) );
}
$w [0] = $y;
$w [1] = $z;
}
XXTEA的算法
核心為
#define MX (z>>5^y<<2) + (y>>3^z<<4)^(sum^y) + (k[p&3^e]^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<n-1; p++) y = v[p+1], z = v[p] += MX;
y = v[0];
z = v[n-1] += MX;
}
return 0 ;
} else if (n < -1) { /* Decoding Part */
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;
}
也是運算不一樣，這個就不寫了，有人已經寫過這方面的代碼了
#include <stdint.h>
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 < num_rounds; i++) {
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (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 < num_rounds; i++) {
v1 −= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
sum −= delta;
v0 −= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
}
v[0]=v0; v[1]=v1;
}
