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].$dict[a5]
这样加密后的结果就是一个长度6-12的字符串，如果字典数组最后3个元素用其他单字符表示，那么结果就固定为6个字符的字符串。
由于初学php不久，对php的函数库不熟悉，求大侠帮忙实现下加密解密算法：
string encrypt(int id,string key)
int decrypt(string text,string key)
echo encrypt(1234, 'abc'), PHP_EOL;echo decrypt( '1TgGSY', 'abc');function encrypt($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', '-','=','*' ); $key = current(unpack('L', sha1($key, 1))); $id ^= $key; $t = str_split(sprintf('%036b', $id), 6); foreach($t as &$v) $v = $dict[bindec($v)]; 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', '-','=','*' ); $dict = array_flip($dict); foreach(str_split($s) as $c) $r[] = sprintf('%06b', $dict[$c]); $id = bindec(join($r)); $key = current(unpack('L', sha1($key, 1))); return $id ^ $key;}
我自己也实现了加密过程，不过看起来就没那么优雅了，执行效率也低点，贴出来衬托下高手风范
$key_string = 'abc';function keyToInt($key) { $key_sha1 = sha1 ( $key ); $first_char = $key_sha1 [0]; if (ord ( $first_char ) > 55) { return hexdec ( (hexdec ( $first_char ) & 7) . substr ( $key_sha1, 1, 7 ) ) | (- 2147483648); } else { return hexdec ( $key_sha1 ); }}function Encrypt($num){ $dict = array('0','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','*','!'); $r1 = $num ^ keyToInt ( $key_string ); $r2 = decbin ( $r1 ); $r3 = array ( bindec ( substr ( $r2, 0, 2 ) ), bindec ( substr ( $r2, 2, 6 ) ), bindec ( substr ( $r2, 8, 6 ) ), bindec ( substr ( $r2, 14, 6 ) ), bindec ( substr ( $r2, 20, 6 ) ), bindec ( substr ( $r2, 26, 6 ) ) ); return $dict [$r3 [0]] . $dict [$r3 [1]] . $dict [$r3 [2]] . $dict [$r3 [3]] . $dict [$r3 [4]] . $dict [$r3 [5]];}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 12341235 oD2LN* 12351236 wqkf8u 12361237 6k=GVU 12371238 bxeCr* 12381239 =W-AOi 12391240 IiQ3e1 12401241 z6uMMA 12411242 WLcnd8 12421243 Rizj*M 12431244 4rHK47 12441245 oD2LNT 12451246 wqkf8Z 12461247 6k=GVJ 12471248 bxeCrE 12481249 =W-AOP 12491250 IiQ3et 12501251 z6uMMP 12511252 WLcndU 12521253 Rizj*p 12531254 4rHK4s 12541255 oD2LNs 12551256 wqkf84 12561257 6k=GVn 12571258 bxeCrL 12581259 =W-AOT 12591260 IiQ3ex 12601261 z6uMM1 12611262 WLcndD 12621263 Rizj*s 12631264 4rHK4h 12641265 oD2LNq 12651266 wqkf83 12661267 6k=GVg 12671268 bxeCr5 12681269 =W-AOH 12691270 IiQ3eP 12701271 z6uMMc 12711272 WLcndE 12721273 Rizj*6 12731274 4rHK4I 12741275 oD2LN= 12751276 wqkf8U 12761277 6k=GVI 12771278 bxeCr9 12781279 =W-AOl 12791280 IiQ3bI 12801281 z6uMhG 12811282 WLcnaY 12821283 Rizj6d 12831284 4rHK3Z 12841285 oD2L*n 12851286 wqkfbP 12861287 6k=Gzj 12871288 bxeC=o 12881289 =W-AEd 12891290 IiQ3bY 12901291 z6uMh* 12911292 WLcnag 12921293 Rizj6v 12931294 4rHK3F 12941295 oD2L*e 12951296 wqkfbJ 12961297 6k=Gzm 12971298 bxeC=N 12981299 =W-AEw 12991300 IiQ3bs 13001301 z6uMhl 13011302 WLcna4 13021303 Rizj6V 13031304 4rHK3u 13041305 oD2L*V 13051306 wqkfbm 13061307 6k=Gz* 13071308 bxeC=- 13081309 =W-AEa 13091310 IiQ3bm 13101311 z6uMhe 13111312 WLcnaS 13121313 Rizj6= 13131314 4rHK38 13141315 oD2L*l 13151316 wqkfbS 13161317 6k=Gz6 13171318 bxeC=q 13181319 =W-AEn 13191320 IiQ3bO 13201321 z6uMhV 13211322 WLcnau 13221323 Rizj61 13231324 4rHK3K 13241325 oD2L*p 13251326 wqkfbv 13261327 6k=Gzw 13271328 bxeC=h 13281329 =W-AE- 13291330 IiQ3bS 13301331 z6uMhj 13311332 WLcna9 1332
在你的设计中，第一节只有 2bit 有效位，所以可在其上再附加4bit信息
而0~15的随机数正好是4bit
算法中，这个随机数起到2个作用
1、调整 key
2、打乱字典
如果不怎么需要太强的保密性，位运算移位就足够了，省点CPU
楼主的解答超赞
加上随机数后，1个整数可对应16种结果，64^6种结果尽数用上，解密时也不用再判断是不是无效字符串了。
是楼主的解答超赞，打错啦
不打了
