PHP 加密解密

1function enToken($txt) {
2    $key   = 'colin';
3    $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-";
4    $nh    = rand(0, 64);
5    $ch    = $chars[ $nh ];
6    $mdKey = md5($key . $ch);
7    $mdKey = substr($mdKey, $nh % 8, $nh % 8 + 7);
8    $txt   = base64_encode($txt);
9    $tmp   = '';
10    $k     = 0;
11    for ($i = 0; $i < strlen($txt); $i++) {
12        $k   = $k == strlen($mdKey) ? 0 : $k;
13        $j   = ($nh + strpos($chars, $txt[ $i ]) + ord($mdKey[ $k++ ])) % 64;
14        $tmp .= $chars[ $j ];
15    }
16
17    return urlencode($ch . $tmp);
18}
19
20function unToken($txt) {
21    $key   = 'colin';
22    $txt   = urldecode($txt);
23    $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-";
24    $ch    = $txt[0];
25    $nh    = strpos($chars, $ch);
26    $mdKey = md5($key . $ch);
27    $mdKey = substr($mdKey, $nh % 8, $nh % 8 + 7);
28    $txt   = substr($txt, 1);
29    $tmp   = '';
30    $k     = 0;
31    for ($i = 0; $i < strlen($txt); $i++) {
32        $k = $k == strlen($mdKey) ? 0 : $k;
33        $j = strpos($chars, $txt[ $i ]) - $nh - ord($mdKey[ $k++ ]);
34        while ($j < 0) $j += 64;
35        $tmp .= $chars[ $j ];
36    }
37
38    return base64_decode($tmp);
39}