Are Audio Captchas Better Than Text Based Captchas?

While viruses and other types of malware are hated by most people, there is one aspect of the internet that might be a little more hated. And that aspect is spam. While most people will only see a virus once or twice in the life of their computer, they will see spam almost every single day. When you go to check your email the spam is there. When you log into Facebook you will see spam on there. And when you are looking at the comments of a popular blog site you will see spam there also. So of course, since spam is so hated, there has to be a way to stop it right?


While there is no way to completely stop spam there are ways to slow it down. When you are in email one of the ways to slow down spam has been to use special filters. These filters use the wisdom of crowd reporting to determine what is spam and what is not. It also relies on special algorithms as well. These algorithms can analyze the email and tell whether it is spam or not. But when you are trying to stop spam outside of the inbox, there is one technology that is used more than any other. And that technology is known as Captcha.

What is Captcha?

Even though the word captcha looks a little weird it is a very important tool that is used on the internet today. You might not recognize the word by itself but I am sure that you have run across one while being on the internet. When you go to a web site and either tried to fill out a form or download a file you will sometimes come across an extra form that you have to fill out. This form will either have one or two strange words that you have to fill out. Once the form is filled in correctly you can then either submit the form or download the file that you originally tried to perform. These are what are known as Captchas and they are there strictly for security reasons.

How does this help against spam?

The reason why there is so much spam generated is because it is so easy to do with computers. With the right program you can easily generate millions of spam messages everyday. So to stop all of those spam messages from hitting the web site they rely on captcha technology. Before you are able to put up a message on the web site you must fill out the captcha form.

You might be asking yourself why don’t the computers just figure out a way to be able to read the captcha message and send the spam anyway. That is the beauty of the whole system. Have you ever noticed how weird the captcha messages look? That is on purpose. The reason why they look like that is so it makes it hard for a computer to be able to read the message. Well at least that was the case in the past. While captchas still work for the most part there has been advances in the technology that allow computers to be able to read captchas better. While it is not one hundred percent, it is still at a high enough percentage where spam is an option again.

This is where audio captchas come into play. In the past, the reason why you would have audio captchas is so that a person who could not see the text captchas would be able to hear the audio version. And this method proved to be very effective. The only problem with the method is that the audio version takes a little more bandwidth than the text version.

But it turns out that we may see more of the audio version than we ever have before. Because more and more spammers have the technology to get around the text versions of the captchas, more web sites are going to start using the audio version. At least in a little more ways than they did before. While it is difficult for a computer to be able to read the text version of a captcha it is even more so to get the audio version. The problem is less that it is hard to read and more that the servers of the spammer would have to process the audio. And that would take a lot longer especially if the audio message changes for each login. But while the audio captcha puts more server strain on the person who is sending spam it is also straining the delivery server as well. While this is a good solution, it is not without its own faults as well.

When you are looking for a solution to stop spammers, you will try anything that you can. Having too much spam on a web site can really take away from it and cause people not to want to visit. If you are getting an inordinate amount of spam all of a sudden you might want to try an audio captcha. It might make the difference.

About Lee Munson

Lee's non-technical background allows him to write about internet security in a clear way that is understandable to both IT professionals and people just like you who need simple answers to your security questions.


  1. […] of the internet that blocks you from completing a form until you fill out a certain box. Sometimes the box will be audio but most of the time it is text and it is filled with squiggly letters that are hard to read. The […]

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