TEA算法
核心为：

#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部分代码非我原创，大家可以了解一下这方面的知识

<?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 );