/**
* Discuz 加密/解密
*
* @param [type] $string [description]
* @param string $operation [description]
* @param string $key [description]
* @param integer $expiry [description]
* @return [type] [description]
*/
function authcode( $string, $operation = 'DECODE', $key = '', $expiry = 0 ) {
$ckey_length = 4;
$key = md5( $key != '' ? $key : C( 'AUTH_CODE' ) );
$keya = md5( substr( $key, 0, 16 ) );
$keyb = md5( substr( $key, 16, 16 ) );
$keyc = $ckey_length ? ( $operation == 'DECODE' ? substr( $string, 0, $ckey_length ): substr( md5( microtime() ), -$ckey_length ) ) : '';
$cryptkey = $keya.md5( $keya.$keyc );
$key_length = strlen( $cryptkey );
$string = $operation == 'DECODE' ? base64_decode( substr( $string, $ckey_length ) ) : sprintf( '%010d', $expiry ? $expiry + time() : 0 ).substr( md5( $string.$keyb ), 0, 16 ).$string;
$string_length = strlen( $string );
$result = '';
$box = range( 0, 255 );
$rndkey = array();
for ( $i = 0; $i <= 255; $i++ ) {
$rndkey[$i] = ord( $cryptkey[$i % $key_length] );
}
for ( $j = $i = 0; $i < 256; $i++ ) {
$j = ( $j + $box[$i] + $rndkey[$i] ) % 256;
$tmp = $box[$i];
$box[$i] = $box[$j];
$box[$j] = $tmp;
}
for ( $a = $j = $i = 0; $i < $string_length; $i++ ) {
$a = ( $a + 1 ) % 256;
$j = ( $j + $box[$a] ) % 256;
$tmp = $box[$a];
$box[$a] = $box[$j];
$box[$j] = $tmp;
$result .= chr( ord( $string[$i] ) ^ ( $box[( $box[$a] + $box[$j] ) % 256] ) );
}
if ( $operation == 'DECODE' ) {
if ( ( substr( $result, 0, 10 ) == 0 || substr( $result, 0, 10 ) - time() > 0 ) && substr( $result, 10, 16 ) == substr( md5( substr( $result, 26 ).$keyb ), 0, 16 ) ) {
return substr( $result, 26 );
} else {
return '';
}
} else {
return $keyc.str_replace( '=', '', base64_encode( $result ) );
}
} 最佳答案
