Four of the biggest problems with CAPTCHA

Posted on December 8, 2017

 

We saw recently that Facebook is to start using selfies as a verification method, presenting an alternative to CAPTCHA, but why the change? What’s the problem with CAPTCHA codes?

You’re probably familiar with the concept of CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart), even if you don’t know what the acronym means. They’re the brief tests you sometimes have to pass to confirm that you’re a human if you want to access a website, retrieve a forgotten password or perform a search on a forum. The idea is that they stop spambots or malicious forms of software from accessing certain areas of sites.

If you’ve done so much as one CAPTCHA in your life, you’ve probably had a bad experience with them. As Facebook is demonstrating, websites seem to be becoming aware of this and are coming up with new ways to find out whether requests are being made by humans or computers.

Here are four of the most common complaints about CAPTCHA, any of which could be used to argue in favour of coming up with an alternative:

1. Hard to read

The most common form of CAPTCHA is the type of test that displays one or more words to the user, often with distorted letters and complex backgrounds. The idea is that image recognition software is not sophisticated enough to complete these tests and it takes a human brain to work out what the words are.

The problem is that sometimes the words are so distorted, they’re too obscured for even a human to read. The internet is full of examples of people who have been left totally stumped by CAPTCHA codes, and it probably doesn’t help that they’re often not real words, so we can’t even have an educated guess at the word if we can pick out some of the letters.

In these cases, CAPTCHAs fail in their basic task of differentiating humans and computers by presenting them with a test that neither can pass.

2. Time consuming

When using the internet, seconds count and we’re usually very impatient. Studies have suggested that a delay of just one second in loading a page can lead to a 16% drop in user satisfaction, thus decreasing page views and conversions.

When people have to pass a test to access a website, this just takes away from the sense of immediacy we’ve come to expect from the web, especially since some CAPTCHAs ask us to do a little more than identify words, like the below example:

They’re doing their best to make it seem appealing by calling it a FunCaptcha, but this is “fun” I didn’t ask for. There are plenty of other sites I can visit if I want to play games, most of which are a bit more exciting than turning a coloured wheel around!

Similarly, you might have seen CAPTCHAs that show you a photo of a street and ask you to click all the squares with a picture of a road sign in. You can easily get them wrong, for example, by noticing that the corner of a sign has drifted into a square and being unsure whether to click it or not.

3. Bots learning fast

Image recognition is getting more advanced by the day, so CAPTCHA needs to keep advancing. That’s why the codes are often so distorted and unclear in the first place.

CAPTCHA codes are actually used to test artificial intelligence (AI). If an AI passes a test, it shows the AI is advanced and, as a consequence, that the CAPTCHA might be insufficient.

4. Impossible for visually impaired

A while ago, we looked at what it’s like for a blind person to use the internet. CAPTCHAs are entirely dependent on sight, so to use them to differentiate between humans and computers seems flawed and even discriminatory. As we’ve seen, CAPTCHAs can be hard for anybody to read, so the problem is even greater for people with poor eyesight or colour blindness, let alone total blindness.

To combat this, some sites offer an alternative audio CAPTCHA, but as the below video shows, these are possibly even harder to decipher and often sound like the noises from our darkest nightmares!

All things considered, it’s perhaps not surprising that Facebook is looking at an alternative to CAPTCHA, and one that gives vain internet users a chance to take a picture of themselves seems as good as any.

Content Team Leader at Engage Web
John works for Engage Web as a Content Team Leader and regularly contributes to the website and programmes of his beloved Chester F.C.
John Murray
  • […] likes to receive spam through their contact forms. This is why many forms use captcha, to stop automated spam being sent through them. Incidentally, ‘captcha’ is an acronym and […]

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