Best way to obfuscate an email address

Question

I'm creating an application that requires passing email addresses around in querystrings and linking to these pages in public documents.

I'd like to prevent my site from becoming spambot heaven, so I'm looking for a simple algorithm (preferably in JavaScript) to encrypt/obfuscate the address so it can be used publicly ina URL without making the email address an easy target.

ex

www.mysite.com/[email protected]
 to
www.mysite.com/page.php?e=aed3Gfd469201

Preferably the result would be a short-ish string that could easily be used in a URL. Any suggestions for what algorithm I could use?

Answer 1

How about simply hashing the email, say with sha256?

Answer 2

RSA-encrypt the data using the public key corresponding to a private key held only by your site.

Base64 and urlencode the result.

Answer 3

Some options coming to my mind :)

• moc.liamg@bob
• [email protected]
• [email protected] (where X is constant)
• [email protected]

Answer 4

you can make a simple function, which would xor each char value with some integer, and make a hex encoded string. (email addresses do not contain non-ascii characters, so it won't complicate with multibyte chars). e.g.:

obfusc = function(s, c) {
  c = c || 0x7f;
  r = "";
  for (i in s) {
    valh = (s.charCodeAt(i) ^ c).toString(16);
    if (valh.length == 1) valh = "0" + valh;
    r += valh;
  };
  return r;
}

deobfusc = function(s, c) {
  c = c || 0x7f;
  r = "";
  for (var i=0; i<(s.length/2); i++) {
    r += String.fromCharCode(parseInt(s.substr(i*2, 2), 16) ^ c)
  };
  return r;
}

addr = "[email protected]";
x = obfusc(addr);
alert(addr + " -> " + x + " -> " + deobfusc(x))

// [email protected] -> 15101a3f1a071e120f131a511c1012 -> [email protected]

Answer 5

The simplest method is simply to store the email addresses within a database table, and pass around a key / ID field that you look up at the point where you want to actually send an email.