Wednesday, 3 August 2011


Ok, time for something a little lighter than of late! This post isn't really anything to do with Linux or Ubuntu (or even computing really), but the concept intrigued me so much that I thought that I'd follow my curiosity and see where it led!

Recently I've been wondering about those strange glyphs that appear next to commenters' names on Wordpress blogs (I've also seen them used in adverts). It turns out that they're called identicons and they are graphical representations of hash values. Someone called Don Park devised the concept (in 2007) to represent IP addresses whilst maintaining user confidentiality - so far, so good: however, it seems to me that there are a couple of inherent flaws with this thinking:

  1. Efficacy relies on users having a static IP address, something that most of us won't enjoy outside of a professional environment.

  2. An IP address (static or otherwise) is no guarantee of a user's identity: the IP address identifies a box on the end of a wire, not the person on the end of the box!

No problem, just use the hash value of an email address to link an identicon to a person and you're good to go!

Well, maybe...

I can think of a couple of potential problems with this approach. But, let's not dwell on the negative; if you want to create your own identicon, you can sign up to a service like Gravatar and register your email address. Here's what mine look like:

Gravatar Default Image
Identicon Image
Mysetery Man

There are other providers or, if you're feeling brave, you can download the source code. Once you've created your account, you can link to your own identicon using:

< img src="" />

Where, HASH is the md5 hash sum of your registered email address (and the img tags are properly closed, unlike the above). The easiest way to get the hash (if you don't want to use the online tool) is to install GtkHash from the Ubuntu Software Centre.

Sources & References:

No comments:

Post a Comment