munge-email-address.php

function munge($address)
{
    $address = strtolower($address);
    $coded = "";
    $unmixedkey = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.@";
    $inprogresskey = $unmixedkey;
    $mixedkey="";
    $unshuffled = strlen($unmixedkey);

    for ($i = 0; $i <= strlen($unmixedkey); $i++) {
        $ranpos = rand(0,$unshuffled-1);
        $nextchar = $inprogresskey{$ranpos};
        $mixedkey .= $nextchar;
        $before = substr($inprogresskey,0,$ranpos);
        $after = substr($inprogresskey,$ranpos+1,$unshuffled-($ranpos+1));
        $inprogresskey = $before.''.$after;
        $unshuffled -= 1;
    }

    $cipher = $mixedkey;

    $shift = strlen($address);

    $txt = "<script type=\"text/javascript\" language=\"javascript\">\n" . "<!-"."-\n" . "// Email obfuscator script 2.1 by Tim Williams, University of Arizona\n" . "// Random encryption key feature by Andrew Moulden, Site Engineering Ltd\n" . "// PHP version coded by Ross Killen, Celtic Productions Ltd\n" . "// This code is freeware provided these six comment lines remain intact\n" . "// A wizard to generate this code is at http://www.jottings.com/obfuscator/\n" . "// The PHP code may be obtained from http://www.celticproductions.net/\n\n";

    for ($j=0; $j<strlen($address); $j++) {
        if (strpos($cipher,$address{$j}) == -1 ) {
            $chr = $address{$j};
            $coded .= $address{$j};
        } else {
            $chr = (strpos($cipher,$address{$j}) + $shift) % strlen($cipher);
            $coded .= $cipher{$chr};
        }
    }

    $txt .= "\ncoded = \"" . $coded . "\"\n" . " key = \"".$cipher."\"\n". " shift=coded.length\n". " link=\"\"\n". " for (i=0; i<coded.length; i++) {\n" . " if (key.indexOf(coded.charAt(i))==-1) {\n" . " ltr = coded.charAt(i)\n" . " link += (ltr)\n" . " }\n" . " else { \n" . " ltr = (key.indexOf(coded.charAt(i))-shift+key.length) % key.length\n" . " link += (key.charAt(ltr))\n" . " }\n" . " }\n" . "document.write(\"<a href='mailto:\"+link+\"'>\"+link+\"</a>\")\n" . "\n" . "//-" . "->\n" . "<" . "/script><noscript>N/A" . "<" . "/noscript>";

    return $txt;
}