Norton Symantec Blog

The Captcha

Most people who have signed up to an Internet service during the past few years will be familiar with a Captcha. The captcha is a box replete with slanted letters and wavy lines, and the customer has to reproduce what they see in a box below.

Traditionally such means are used to filter out Internet spammers. Irregular shapes and a scrambled background combine to confuse the codes that spammers employ – stopping them from being able to infiltrate various search engines and online shops.

Alan Turing

The idea was developed by Yahoo and stemmed from an experiment conducted by the famed mathematician Alan Turing over fifty years ago. Turing has proposed to develop a test which distinguished the varying abilities of computers and people, a test that caused the computer to ‘think’. He argued that the test would be passed if a machine could carry on a conversation in a manner that was indistinguishable from a human.

The rise of the bots

The constant evolution of online threats has now even brought this valued security measure under threat. The Guardian has noted how hackers have now developed bots that can permeate these captchas – appearing to have developed almost the same ability to read the text as humans. Websense, an Internet security company has announced that these new bots were perfected early this year and are already being found to be active on the Internet. The industry has deemed this latest news to be disquieting; ‘a severe blow to online security.’