1 function rc4 ($pwd, $data)//$pwd密钥 $data需加密字符串
2 {
3 $key[] ="";
4 $box[] ="";
5
6 $pwd_length = strlen($pwd);
7 $data_length = strlen($data);
8
9 for ($i = 0; $i < 256; $i++)
10 {
11 $key[$i] = ord($pwd[$i % $pwd_length]);
12 $box[$i] = $i;
13 }
14
15 for ($j = $i = 0; $i < 256; $i++)
16 {
17 $j = ($j + $box[$i] + $key[$i]) % 256;
18 $tmp = $box[$i];
19 $box[$i] = $box[$j];
20 $box[$j] = $tmp;
21 }
22
23 for ($a = $j = $i = 0; $i < $data_length; $i++)
24 {
25 $a = ($a + 1) % 256;
26 $j = ($j + $box[$a]) % 256;
27
28 $tmp = $box[$a];
29 $box[$a] = $box[$j];
30 $box[$j] = $tmp;
31
32 $k = $box[(($box[$a] + $box[$j]) % 256)];
33 $cipher .= chr(ord($data[$i]) ^ $k);
34 }
35
36 return $cipher;
37 }
