<pre class="prettyprint lang-php">&lt;?php

function encode($str) { $len = strlen($str); $result = ''; for ($i = 0; $i < $len; $i++) { $temp = ord($str[$i]); if ($temp > 64 && $temp < 91) { $temp = $temp + 16; if ($temp > 90) { $temp = $temp - 26; } } else if ($temp > 96 && $temp < 123) { $temp = $temp + 16; if ($temp > 122) { $temp = $temp - 26; } } $result .= chr($temp); } return $result; }

function decode($str) { $len = strlen($str); $result = ''; for ($i = 0; $i < $len; $i++) { $temp = ord($str[$i]); if ($temp > 64 && $temp < 91) { $temp = $temp - 16; if ($temp < 65) { $temp = $temp + 26; } } else if ($temp > 96 && $temp < 123) { $temp = $temp - 16; if ($temp < 97) { $temp = $temp + 26; } } $result .= chr($temp); } return $result; }

// 使用 $str = 'Hello World!'; $encodeStr = encode($str); echo $encodeStr; // Uryyb Jbeyq! $decodeStr = decode($encodeStr); echo $decodeStr; // Hello World!