The Tech Blog of Ken

Read the squiggles

Ever get stuck on one of those login screens where you have to pick out some hard-to-read text in a squiggly, multi-colored image? Those images are called CAPTCHAs, which is an acronym for Completely Automated Public Turing test to tell Computers and Humans Apart. What a deliciously geeky acronym. Wikipedia has a pretty good article on the history and current state of the captcha, with links to current captcha implementations.

It's interesting to note that by definition, the Captcha doesn't have to be an image with text. It just has to be some kind of task that's easy for a human to solve, but difficult for a machine. It could be a sound clip or an easily identified image, like a picture of an animal.

I find the social engineering used to trick people into deciphering captchas to be pretty amusing. It just goes to show that you just can't devise an algorithm to defeat human nature.

Technorati Tags: security

Firefox security update

If you haven't heard already, Firefox has been updated to version 1.0.7 to fix a security problem. Don't forget to update your computer(s). BTW, the next major version, Firefox 1.5, will have built-in updating to make security patches even easier to install, with less to download (not like FF is that big to begin with).

Technorati Tags: firefox, security

Setting feed-specific persistence in NetNewsWire

This morning, I had over 85000 unread items in NetNewsWire (yes 85k). The majority of these are from subscriptions to frequently-updated news sites like BBC and BoingBoing, and because I've configured NNW to keep news items for 999 days. I don't know how I missed this, but the Info panel of each feed has a setting where you can configure the persistence to expire after a set number of days or when the items disappear from the feed. You can also set persistence on a group level. By grouping all the high-traffic news feeds together and changing the persistence to expire after a shorter period of time (a month or so), I reduced the number of unread to around 55k.

Not that having so many unread messages is really a big deal - after a couple of thousand you don't really bother to try to read all of them. All those unread messages do have to be saved somewhere though, so deleting them can only be a good thing. Note that changing the persistence settings also determines how long read headlines are saved, so it's worth it to flush out some of the old ones.