February 26, 2007, 9:35 am
Visual Identity: Identicon
by Lisa Agustin
Filed under: Implementation, Technology, Visual Explanation
Reading a string of comments on a blog is not the most stimulating user experience. Moreover, if a blog post is riveting enough to start an online conversation via comments, following the exchanges between participants may require closer reading to see who said what. Enter the Identicon. Programmer Don Park developed the Identicon as a way of enhancing the commenter’s identity by using a privacy protecting derivative of each commenter’s IP address to build a 9-block image to identify the writer. Referred to in its debut as “IP-ID,” the Identicon is written in Java and based on the first four bytes of SHA-1 (Secure Hash Algorithm). The Identicon’s visualization consists of a small quilt of 9 blocks that uses 3 types of patches, out of 16 available, in 9 positions. To try this yourself, visit Park’s blog and scroll down to the comment form, which will display your current Identicon. Mine at the time of this writing:
How it works: the Identicon code selects 3 patches: one for center position, one for 4 sides, and one for 4 corners. There are additional details in the code for determining positioning, rotation, color, and inversion of the blocks.
For users with dynamic IP addresses, their Identicons will change over time. However, according to Park, it doesn’t appear to change often enough to affect identification beyond a “typical comment activity cluster” (presumably a single session during which a comment might be posted). Park adds:
I originally came up with this idea to be used as an easy means of visually distinguishing multiple units of information, anything that can be reduced to bits. It’s not just IPs but also people, places, and things. IMHO, too much of the web what we read are textual or numeric information which are not easy to distinguish at a glance when they are jumbled up together.
Besides the intended purpose of identifying individual users among a sea of many (e.g., wiki authors, customer tracking in CRM tools, etc.), there may be other uses as well, such as identification of individual computers within a large network. Plus the Identicon seems to be gaining in popularity: a PHP version is now available, as well as one that works for WordPress.
Comments
Since most blogs require a name, the thing I find interesting about the identicon concept is that it can indicate if a commenter is using multiple identities. (It indicates, but doesn’t prove, since multiple people may be using a fixed IP connection, or even the same computer.)
I have to say, though, that the identicons on Park’s blog look like snowflakes to me. Sure they’re all different, but the differences don’t stand out as much as the generic similarity. I saw the color differences more clearly than the pattern differences.
Posted by Henry Woodbury on February 26, 2007 at 10:41 am