自定义加密算法的实现解决办法

自定义加密算法的实现
本帖最后由 feiniaoflyer 于 2014-05-01 13:16:02 编辑

由于要传一个需要保密的ID，因此用到对称加密，但mcrypt_encrypt算法加密后字符串太长，因此想实现一个自定义加密算法，想法如下

首先先对key计算sha1，取结果的前32bit，然后跟要加密整数进行异或，得到一个加密后的32bit结果

对结果分组：2bit | 6bit | 6bit | 6bit | 6bit | 6bit

各个组分别取名为：a0、a1、a2、a3、a4、a5

另定义一个长度64的字典数组

$dict=array('1','2','3','4','5','6','7','8','9',
'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
'01','02','03');

将前面每个分组的值作为字典数组的下标，则加密结果为：$dict[a0].$dict[a1].$dict[a2].$dict[a3].$dict[a4].$dict[a5]

这样加密后的结果就是一个长度6-12的字符串，如果字典数组最后3个元素用其他单字符表示，那么结果就固定为6个字符的字符串。

由于初学php不久，对php的函数库不熟悉，求大侠帮忙实现下加密解密算法：

string encrypt(int id,string key)

int decrypt(string text,string key)





------解决方案--------------------

------解决方案--------------------
学习了，厉害。
------解决方案--------------------
这个够乱的了吧

$id = 1234;
$key = 'aaa';
for($i=1; $i<100; $i++) {
  printf("%-10d %s %s\n", $id, $s = encrypt($id++, $key), decrypt( $s, $key));
}

function encrypt($id, $key) {
  $dict = array('1','2','3','4','5','6','7','8','9',
    'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
    'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
    '-','=','*'
  );
  $n = rand(0, 15);
  srand($n);
  $key = current(unpack('L', substr(sha1($key, 1), $n)));
  $id ^= $key;
  $t = str_split(sprintf('%04b%032b', $n, $id), 6);
  foreach($t as $i=>&$v) {
    $v = $dict[bindec($v)];
    if($i == 0) shuffle($dict);
  }
  return join($t);
}

function decrypt($s, $key) {
  $dict = array('1','2','3','4','5','6','7','8','9',
    'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
    'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
    '-','=','*'
  );
  $m = array_search($s{0}, $dict);
  $n = $m >> 2;
  srand($n);
  shuffle($dict);
  $dict = array_flip($dict);
  foreach(str_split($s) as $i=>$c) {
    $r[] = sprintf('%06b', $i==0 ? $m&0x03 : $dict[$c]);
  }    
  $id = bindec(join($r));
  $key = current(unpack('L', substr(sha1($key, 1), $n)));
  return $id ^ $key;
}

1234       4rHK4B 1234
1235       oD2LN* 1235
1236       wqkf8u 1236
1237       6k=GVU 1237
1238       bxeCr* 1238
1239       =W-AOi 1239
1240       IiQ3e1 1240
1241       z6uMMA 1241
1242       WLcnd8 1242
1243       Rizj*M 1243
1244       4rHK47 1244
1245       oD2LNT 1245
1246       wqkf8Z 1246
1247       6k=GVJ 1247
1248       bxeCrE 1248
1249       =W-AOP 1249
1250       IiQ3et 1250
1251       z6uMMP 1251
1252       WLcndU 1252
1253       Rizj*p 1253
1254       4rHK4s 1254
1255       oD2LNs 1255
1256       wqkf84 1256
1257       6k=GVn 1257
1258       bxeCrL 1258
1259       =W-AOT 1259
1260       IiQ3ex 1260
1261       z6uMM1 1261
1262       WLcndD 1262
1263       Rizj*s 1263
1264       4rHK4h 1264
1265       oD2LNq 1265
1266       wqkf83 1266