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(PHP 4 >= 4.2.0, PHP 5)
str_rot13 — Führt die ROT13-Transformation auf einen String aus
Diese Funktion führt die ROT13-Transformation auf die Zeichenkette str aus und liefert den Ergebnisstring zurück.
Die ROT13-Kodierung verschiebt einfach jeden Buchstaben um 13 Stellen im Alphabet. Zeichen, die keine Buchstaben sind, bleiben unverändert. Verschlüsselung und Entschlüsselung werden von derselben Funktion durchgeführt. Bei Übergabe eines verschlüsselten Strings wird der Originalstring zurückgegeben.
Die Eingabezeichenkette.
Gibt die ROT13-Version der angegebenen Zeichenkette zurück.
Beispiel #1 str_rot13()-Beispiel
<?php
echo str_rot13('PHP 4.3.0'); // CUC 4.3.0
?>
| Version | Beschreibung |
|---|---|
| 4.3.0 | Das Verhalten dieser Funktion wurde korrigiert. Vor der Korrektur wurde der str-Parameter selbst ebenfalls verändert, als wenn er als Reference übergeben worden wäre. |
Here's my implementation of a str_rot that takes a custom offset. It's faster than the others here because it allocates the output string in one go instead of tacking on characters one at a time. It can handle positive or negative offsets of any size, and it fixes everything up to ensure only upper and lower case letters are translated and that they wrap around correctly within the alphabet.
<?php
function str_rot($s, $n = 13) {
$n = (int)$n % 26;
if (!$n) return $s;
for ($i = 0, $l = strlen($s); $i < $l; $i++) {
$c = ord($s[$i]);
if ($c >= 97 && $c <= 122) {
$s[$i] = chr(($c - 71 + $n) % 26 + 97);
} else if ($c >= 65 && $c <= 90) {
$s[$i] = chr(($c - 39 + $n) % 26 + 65);
}
}
return $s;
}
?>
This ROT13 variant is different from my earlier version in that it retains 'ethnicity'. For example, a Chinese text when encrypted will remain Chinese, and the string will not be making sense (the real meaning will be encrypted). Just look at the code and you will understand.
<?php
function unichar2ords($char, $encoding = 'UTF-8') {
$char = mb_convert_encoding($char, 'UCS-4', $encoding);
$val = unpack('N', $char);
return $val[1];
}
function ords2unichar($ords, $encoding = 'UTF-8'){
$char = pack('N', $ords);
return mb_convert_encoding($char, $encoding, 'UCS-4');
}
function mbStringToArray ($string, $encoding = 'UTF-8') {
if (empty($string)) return false;
for ($strlen = mb_strlen($string, $encoding); $strlen > 0; ) {
$array[] = mb_substr($string, 0, 1, $encoding);
$string = mb_substr($string, 1, $strlen, $encoding);
$strlen = $strlen - 1;
}
return $array;
}
function unicodeRotN($str, $offset, $encoding = 'UTF-8') {
$val = '';
$array = mbStringToArray ($str, $encoding = 'UTF-8');
$len = count($array);
for ($i = 0; $i < $len; $i++) {
$val .= ords2unichar(unichar2ords($array[$i], $encoding) + $offset, $encoding);
}
return $val;
}
// example
$original = '中國是我的家'; // means "China is my home"
$encrypted = unicodeRotN($string, 13); // 为團昼戞皑寃 means "Ñ Ai injustice for the Mission Day" (Google translation)
$decrypted = unicodeRotN($encrypted, -13); // 中國是我的家
?>
Here is my ROT13 function that works for all possible characters and not just ASCII. It can be used on Chinese, Japanese, ....
<?php
function rot13encrypt ($str) {
return str_rot13(base64_encode($str));
}
function rot13decrypt ($str) {
return base64_decode(str_rot13($str));
}
// example
$string = '中國是我的家';
$encrypted = rot13encrypt ($string); // produces 5Yvg5MlY5cvi5bvE55dR5n62
$decrypted = rot13decrypt ($encrypted); // produces 中國是我的家
?>
resubmitting updated function in re:#76975
<?php
function asc_shift($str,$offset=0) {
$new = '';
for ($i = 0; $i < strlen($str); $i++)
$new .= chr(ord($str[$i])+$offset);
return $new;
}
?>
because as of PHP 6, $str{$i} is deprecated.
This is recursive function to shift the component letters of a string left or right in the ascii table.
I've left it simple as it suits my needs, but you may want to include error checking for a null string and also put bounds in place, or make it actually rotate around the whole character set rather than just shifting the string up or down.
function asc_shift($string, $amount) {
$key = substr($string, 0, 1);
if(strlen($string)==1) {
return chr(ord($key) + $amount);
} else {
return chr(ord($key) + $amount) . asc_shift(substr($string, 1, strlen($string)-1), $amount);
}
}
For example:
<?php
echo asc_shift("TESTING12345@", 5);
?>
shifts every character up 5 ascii positions, resulting in this string:
YJXYNSL6789:E
In reverse:
<?php
echo asc_shift("YJXYNSL6789:E", -5);
?>
shifts every character down 5 ascii positions, resulting in this string:
TESTING12345@
here's my rot function, it works anyway
<?php
/**
* preforms the rotation algorithm on the passed in string
*/
function _rot( $str , $dist=13 ){
if( !is_numeric($dist) || $dist < 0){
$dist = 13;
}
$u_lower = 65; $u_upper = 90;
$l_lower = 97; $l_upper = 122;
$char_count = ($u_upper - $u_lower) +1;
while( $dist > $char_count ){
$dist -= $char_count;
}
$newstr = '';
for( $i=0; $i<strlen($str); ++$i){
$c = ord($str[$i]);
/*
* Check if the character is within the bounds of our function (a-zA-z)
* if not it gets tacked on to the string as is and we move on to the
* next one.
*/
if( $c<$u_lower || $c>$l_upper || ( $c>$u_upper && $c <$l_lower ) ){
$newstr .= chr($c);
continue;
}
$lower = ( $c<=$u_upper?$u_lower:$l_lower);
$upper = ( $c<=$u_upper?$u_upper:$l_upper);
$c += $dist;
if( $c > $upper){
$c = (($c - $upper) + ($lower-1));
}
$newstr .= chr($c);
}
return $newstr;
}
?>
<?php
/**
* Rotate each string characters by n positions in ASCII table
* To encode use positive n, to decode - negative.
* With n = 13 (ROT13), encode and decode n can be positive.
*
* @param string $string
* @param integer $n
* @return string
*/
function rotate($string, $n) {
$length = strlen($string);
$result = '';
for($i = 0; $i < $length; $i++) {
$ascii = ord($string{$i});
$rotated = $ascii;
if ($ascii > 64 && $ascii < 91) {
$rotated += $n;
$rotated > 90 && $rotated += -90 + 64;
$rotated < 65 && $rotated += -64 + 90;
} elseif ($ascii > 96 && $ascii < 123) {
$rotated += $n;
$rotated > 122 && $rotated += -122 + 96;
$rotated < 97 && $rotated += -96 + 122;
}
$result .= chr($rotated);
}
return $result;
}
$enc = rotate('string', 6);
echo "Encoded: $enc<br/>\n";
echo 'Decoded: ' . rotate($enc, -6);
?>
Perhaps someone will find this useful ;)
<?
function rotN($s, $n){
$s2 = "";
for($i = 0; $i < strlen($s); $i++){
$char2 = $char = ord($s{$i});
$cap = $char & 32;
$char &= ~ $cap;
$char = $char > 64 && $char < 123 ? (($char - 65 + $n) % 26 + 65) : $char;
$char |= $cap;
if($char < 65 && $char2 > 64 || ($char > 90 && $char < 97 && ($char2 < 91 || $char2 > 96))) $char += 26;
else if($char > 122 && $char2 < 123) $char -= 52;
if(strtoupper(chr($char2)) === chr($char2)) $char = strtoupper(chr($char)); else $char = strtolower(chr($char));
$s2 .= $char;
}
return $s2;
}
?>
It takes any string, $s, and any ROT value, $n. Just like str_rot13, it's both an encoder and decoder. To decode an encoded string, just pass -$n instead of $n.
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