| 上面的是TEA的算法，XTEA的算法为：
#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;
}
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 << 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;
}
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