base64_decode技巧

$str = strtr($str, '-*.', '+/=');  在base64的时候对字符串做替换。。。。

function decryptString($str, $key = '123456') {
$str = strtr($str, '-*.', '+/=');
$data = base64_decode($str);
$ivlength = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CFB);
$iv = substr($data, 0, $ivlength);
$encrypted = substr($data, $ivlength);
return mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $encrypted, MCRYPT_MODE_CFB, $iv);
}

function encryptString($str, $key = '123456') {
$iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CFB), MCRYPT_RAND);
$encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $str, MCRYPT_MODE_CFB, $iv);
$en_text = base64_encode($iv . $encrypted);
$en_text = strtr($en_text, '+/=', '-*.');
return $en_text;
}