Hash Generator

This page contains JavaScript that will accept input and create various forms of hashes from it.

You will need to have JavaScript enabled to use this page

You can use this to create an obfuscated e-mail signature for use in Foaf or RSS documents.

Enter your e-mail address here:

If you're using this for an e-mail address be SURE to start it with mailto:

Then click one of these buttons to see it hashed into that format:

Type	Hashed Result


	Use this inside a FoaF document:

So what will having a hash of an address do for you?

A hash can only be un-hashed with a previously known key. Here your address is being signed with itself. That means the hash can only be untangled by someone that's already got your e-mail address.

Ok, so how would the hash get used?

Let's say you sign up for a service like Syndic8.com and give them your e-mail address. They can store a hash of your address. If, at some later time, your feed develops some sort of problem the hash can be used to cross reference it with the address you'd already supplied. It's sort of like putting an identifying mark on it instead of an e-mail address.

That's sort of geeky sounding, I know, but here's what's happening:

You sign up for a service and give it your e-mail address
The service records your e-mail address and internally creates a hash of it
You create that same hash (here) and put it inside your RSS feeds

At some point in the future if your feed is found to have problems that hash could be used to find your e-mail address. The process would go like this:

Your feed is read and the hash is found
The hash is compared against the previously seen hashes
A matching hash is found and the stored e-mail address is retrieved.
The hash itself is never decoded, it's simply used as a pointer.

Your address would already be known on the server side. The hash in your feed would be linked to it's matching hash in the database. The hash cannot be unscrambled without knowing the address itself, the hash is simply a pointer. Yes, anyone that has your e-mail address already could create a hash. The point here is to use a simple way to hide your e-mail address. If they've already got it, well, there'd be no point in hashing it.

The only reason for putting a hash in your feed is to allow someone that's being responsible to match up the feed with the address they already have for you. The reason to use a hash like SHA1 is to make it possible to more than one such service to utilize it. Remember, they're already going to have your address, the hash is just a pointer to it.

Note about privacy:

The code on this page runs entirely in YOUR browser. Nothing runs over here at the server. So anything you enter here is NOT recorded in a log file. Spam is bad enough, we're not going to add to it.

The code is derived from the work done by Paul Johnston.

Thanks go out to Leandro for his assistance in getting this to work in Mozilla.

If you'd like, you can Trackback this page. See this page for the link.