php代码实现如下：
<?php
class price_model{
function base64url_decode($data) {
$trans = array("-" => "+", "_" => "/");
return base64_decode(str_pad(strtr($data, $trans), strlen($data) % 4, '=', STR_PAD_RIGHT));
}
function base64url_encode($data) {
$trans = array("+" => "-", "/" => "_");
$ret = strtr(base64_encode($data), $trans);
return $ret;
}
function decode_price($base64_text) {
$s1 = $this->base64url_decode($base64_text);
$iv = substr($s1, 0, 16);
$p = substr($s1, 16, 8);
$sig = substr($s1, 24, 4);
$enc_key = $this->config->item('enc_key');
$pad = hash_hmac('sha1', $iv, hex2bin($enc_key));
$price = $this->xor_str($p, substr(hex2bin($pad), 0, 8), 8);
$ret = array('price'=>hexdec($price), 'sig'=>$this->sig($price, $iv, $sig));
return $ret;
}
/**
* @param $price 为十进制
* @param $iv 前8位带上时间戳
*/
function encode_price($price, $iv) {
if(strlen(''.$price)<16) {
$price = sprintf('%016x', $price);
}
$pad = substr(hash_hmac('sha1', hex2bin($iv), hex2bin($this->config->item('enc_key'))), 0, 16);
$enc_price = $this->xor_str(hex2bin($pad), hex2bin($price), 8);
$sig = substr(hash_hmac('sha1', hex2bin($price.$iv), hex2bin($this->config->item('sig_key'))), 0, 8);
$ret = $this->base64url_encode(hex2bin($iv.$enc_price.$sig));
for($i=0;$i<2;$i++) {
if($ret[strlen($ret)-1]=='=') {
$ret = substr($ret, 0, strlen($ret)-2);
}
}
return $ret;
}
function sig($price, $iv, $sig) {
$sig_key = $this->config->item('sig_key');
$sig1 = hex2bin(hash_hmac('sha1', hex2bin(sprintf('%016x', $price)).$iv, hex2bin($sig_key)));
$len = strlen($sig);
return substr($sig1, 0, $len)===substr($sig, 0, $len);
}
function xor_str($s1, $s2, $len) {
$ret = '';
for($i=0;$i<$len;$i++) {
$ret .= sprintf('%02x', ord($s1[$i])^ord($s2[$i]));
}
return $ret;
}
}
