YA: Simple Lowercase String Offsetter

<?php
/*    Response to Yahoo Answers Question    */


/*    Your's Cleaned Up and Working    */
$alphaex = range('a','z');

$inputwordex = range('a','e');
echo '<pre>';
print_r($inputwordex);
echo '</pre>';

$iword = 0;
$decodeword = "";
while ($iword < 5){
    $ialpha = 0;
    $found = "N";
    while ($found == "N"){
        if ($inputwordex[$iword] == $alphaex[$ialpha]) {
            $i = $ialpha + 24;
            $i = $i % count($alphaex); // Remainder of $i / count($alphaex) or $i / 26; Remeber that a is = 0 and z is 25; Array Indexes start at 0 not 1;
            $decodeword .= $alphaex[$i];
            echo "<br>" . $decodeword;
            $found = "Y";
        }else{
            $ialpha += 1;
        }
    }
    $iword += 1;
}
echo "<br>";
echo $decodeword;



/*    Using Functions to offset a string. Only Does LowerCase    */
function offset_encode($str, $offset=24){
    $alphaex = range('a','z');
    $r = '';
    for($i=0; $i < strlen($str); ++$i){
        $num = (array_search($str{$i}, $alphaex) + $offset) % count($alphaex);
        $r .= $alphaex[$num];
    }
    return $r;
}
function offset_decode($str, $offset=24){
    $alphaex = range('a','z');
    $r = '';
    for($i=0; $i < strlen($str); ++$i){
        $num = (array_search($str{$i}, $alphaex) - $offset);
        if($num < 0){
            $num += count($alphaex);
        }
        $r .= $alphaex[$num];
    }
    return $r;
}
$offset = 24;
$str = 'abcde';
$encoded = offset_encode($str, $offset);
$decoded = offset_decode($encoded, $offset);

echo 'String: ' . $str . '<br>' . 'Encoded: ' . $encoded . '<br>' . 'Decoded: ' . $decoded . '<br>';


/*    String Encoding and Decoding    */
echo '<h3>str_encode() and str_decode()</h3>';
defined('STR_SALT')? null : define('STR_SALT','Dwnp=MduTHp0Bn4x>u0p:hf=*[smx5T+ieL9Zr-.Wc4Xc{r0rjjT[Qhv,v{$)sGl');

function str_encode($i){
    return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5(STR_SALT), ($i . sha1(STR_SALT) . STR_SALT) , MCRYPT_MODE_CBC, md5(md5(STR_SALT))));
}
function str_decode($i){
    return str_replace(Array(sha1(STR_SALT),STR_SALT),'', rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5(STR_SALT), base64_decode($i), MCRYPT_MODE_CBC, md5(md5(STR_SALT))), "\0"));
}
$str = 'abcde';
$encoded = str_encode($str);
$decoded = str_decode($encoded);
echo 'String: ' . $str . '<br>' . 'Encoded: ' . $encoded . '<br>' . 'Decoded: ' . $decoded . '<br>';