PHP-simple symmetric encryption algorithm and conversion function between string and hexadecimal

/**
* Encryption using simple symmetric encryption algorithm
* @param String $string The string that needs to be encrypted
* @param String $skey Encryption EKY
* @return String
*/
function encode($string = '', $skey = 'textphp') {
　　$skey = str_split(base64_encode($skey));
　　$strArr = str_split(base64_encode($string));
　　$strCount = count($strArr);
　　foreach ($skey as $key => $value) {
　　　　$key < $strCount && $strArr[$key].=$value;
　　}
　　return str_replace('=', 'O0O0O', join('', $strArr));
}

/**
* Decryption of simple symmetric encryption algorithm
* @param String $string The string to be decrypted
* @param String $skey Decryption KEY
* @return String
*/
function decode($string = '', $skey = 'textphp') {
　　$skey = str_split(base64_encode($skey));
　　$strArr = str_split(str_replace('O0O0O', '=', $string), 2);
　　$strCount = count($strArr);
　　foreach ($skey as $key => $value) {
　　　　$key < $strCount && $strArr[$key][1] === $value && $strArr[$key] = $strArr[$key][0];
　　}
　　return base64_decode(join('', $strArr));
}

//字符串转换成16进制
function str2hex($str, $encoded = 'GBK') {
　　$hex = '';
　　if ($encoded == 'GBK') {
　　　　$str = mb_convert_encoding($str, 'GBK', 'UTF-8');
　　}
　　for ($i = 0, $length = mb_strlen($str); $i < $length; $i++) {
　　　　$hex .= dechex(ord($str{$i}));
　　}
　　return $hex;
}

//16进制转换成字符串
function hex2str($hex, $encoded = 'GBK') {
　　$str = '';
　　$arr = str_split($hex, 2);
　　foreach ($arr as $bit) {
　　　　$str .= chr(hexdec($bit));
　　}
　　if ($encoded == 'GBK') {
　　　　$str = mb_convert_encoding($str, 'UTF-8', 'GBK');
　　}
　　return $str;
}

以上就介绍了php-简单对称加密算法和字符串与十六进制之间的互转函数，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。