Captchas: What They Mean for you.

We’ve all had the experience of typing ridiculous letters or having google tell us to pick out the street signs in photos. For Most of us its no more than an annoyance. But what if these captchas tell us more about our use of computers than we realized?

The backronym means: Completely-Automated-Public-Tuning test to tell-Computers and-Humans-Apart.

Essentially these exist to challenge the user of a particular website and determine whether the visitor is human.

Modern text-based captchas have three distinct characteristics that are being tested:

1. Invariant recognition refers to the ability to recognize the large amount of variation in the shapes of letters. There are nearly an infinite number of versions for each character that a human brain can successfully identify. The same is not true for a computer, and teaching it to recognize all those differing formations is an extremely challenging task.

2. Segmentation, or the ability to separate one letter from another, is also made difficult in CAPTCHAs, as characters are crowded together with no white space in between.

3. Context is also critical. The CAPTCHA must be understood holistically to correctly identify each character. For example, in one segment of a CAPTCHA, a letter might look like an “m.” Only when the whole word is taken into context does it become clear that it is a “u” and an “n.”

Each of these problems poses a significant challenge for a computer, even in isolation. The presence of all three at the same time is what makes CAPTCHAs difficult to solve. Supposedly, humans are far better at these three things than machines. However, there have been quite a few instances of captchas being defeated by an array of tactics.



Along with Captchas, you may also come across this: “Unusual traffic from your computer network” typically from google either through chrome/chromium or through the search engine.

These messages occur if devices on your network are sending automated traffic to google. They can occur for lots of other reasons e.g. someone piggybacking off your network or spoofing your IP from some kind of VPN or similar system. VPNS in particular, can cause an annoyance for Google, especially if your ISP doesn’t take VPNs too kindly.

There are lots of things you can do about Captchas and unusual traffic, even if you aren’t tech-savy. Chief among these is contacting your network administrator, if you work on a network.

Its also important that you check your computer for Malware. There are kinds of malware which can cause this kind of message.

See Also – this awesome article I wrote on dealing with potential Malware!

Checking to ensure your firewall is up is an important step & updating your anti-virus definitions if you use anti-virus.

Finally, resetting your network modem or router is also a measure that you can take, especially on your home network. I would suggest that you give it a few minutes then fire it up again.

Ron Motilall is a Linux user and a huge technology enthusiast. He graduated with a LLB in Law from the University of Guyana and believes the late 90’s was the most important period for human innovation. Ron describes himself as a learner and teacher with extensive knowledge about open source technology and its role in changing innovation, you can read more of his articles here.