カスタム暗号化アルゴリズムの実装ソリューション

$id = 1234;<br />$key = 'aaa';<br />for($i=1; $i<100; $i++) {<br />  printf("%-10d %s %s\n", $id, $s = encrypt($id++, $key), decrypt( $s, $key));<br />}<br /><br />function encrypt($id, $key) {<br />  $dict = array('1','2','3','4','5','6','7','8','9',<br />    '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',<br />    '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',<br />    '-','=','*'<br />  );<br />  $n = rand(0, 15);<br />  srand($n);<br />  $key = current(unpack('L', substr(sha1($key, 1), $n)));<br />  $id ^= $key;<br />  $t = str_split(sprintf('%04b%032b', $n, $id), 6);<br />  foreach($t as $i=>&$v) {<br />    $v = $dict[bindec($v)];<br />    if($i == 0) shuffle($dict);<br />  }<br />  return join($t);<br />}<br /><br />function decrypt($s, $key) {<br />  $dict = array('1','2','3','4','5','6','7','8','9',<br />    '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',<br />    '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',<br />    '-','=','*'<br />  );<br />  $m = array_search($s{0}, $dict);<br />  $n = $m >> 2;<br />  srand($n);<br />  shuffle($dict);<br />  $dict = array_flip($dict);<br />  foreach(str_split($s) as $i=>$c) {<br />    $r[] = sprintf('%06b', $i==0 ? $m&0x03 : $dict[$c]);<br />  }    <br />  $id = bindec(join($r));<br />  $key = current(unpack('L', substr(sha1($key, 1), $n)));<br />  return $id ^ $key;<br />}<br />

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