What are captchas and how do they work

In this article we will provide you with some information to learn more about captchas. Find out what they're for, how to use them, and what types exist.

You don't have to be a computer expert or an experienced online user to have heard of captcha or come across them while surfing the web. Perhaps you didn't know exactly what their purpose was and have often found yourself intuitively responding to prompts. Well, the captcha are not a riddle to test your patience, they are, in fact, security systems that have the important function of protecting your data from spam and password decryption. Here is some info to learn more.

Captcha: what it means

The term captcha is an acronym, short for "Completely Automated Public Turing test to tell Computers and Humans Apart". In Italian, it can be translated as "Completely automated public Turing test to tell computers and humans apart". Like most of the words in the computer industry, which often use everyday words and phrases, it is a phonetic reference to the English expression "Caught you".

On the origins of captcha

The history of captcha dates back to 1997, when they were designed by AltaVista's research and development department, headed by Andrei Broder, to prevent bots from adding URLs to their search engine. According to Broder, the introduction of this technology decreased spam by more than 95%. The term captcha, however, was coined in 2000 by Luis von Ahn, Manuel Blum and Nicholas J. Hopper of Carnegie Mellon University in Pittsburgh and John Langford of IBM, the oldest and one of the most important computer companies in the world.

This research team then developed and spread another idea of captcha testing, meaning any type of program that can distinguish between individuals and computers. The team developed a number of different types of tests, many of which were widely used by the web portal Yahoo! Captchas were readily adopted in the Internet world and used for various purposes mainly to prevent spam and automatic data extraction from websites.

Captcha: what is it and what types are there

The captcha is an element that allows a form or other interaction process to identify human presence and invalidate any malicious automatisms. There are various types of codes. There is the "classic" captcha which involves the entry of alphanumeric elements: numbers and upper and lower case letters in a given field. Often the characters are deformed, rotated, curved, combined with additional graphic components, such as lines, color tones or visual interference.

In addition to text captcha, there are procedures that are based on images. Here, you need to click on the proposed image sections to easily pass the verification. For the visually impaired and blind people, a visual captcha can be a hindrance. To ensure better usability, it's a good idea to set up captcha that can be verified on multiple sensory channels, providing an alternative button with which users can listen to an audio recording.

Captcha: how to use them in your sites or blogs

The captcha is an important step to protect the security of a website without disrupting the user experience. In fact, at first glance, one might ask: why complicate their life? We know how much the user experience is based on personal perceptions such as usefulness, ease of use and system efficiency. È, chiaramente, importante semplificare tutti i vari passaggi su di un sito web o blog, specialmente quelli che consentono alla persona di trasformarsi in lead o cliente.

Dunque, potrebbe sembrare più conveniente eliminare tutti i captcha dal tuo sito e lasciare libero spazio all’invio dei messaggi o alle azioni dell’utente ricercate. La soluzione migliore è ottimizzare l’utilizzo dei captcha stessi. Per inserire un captcha sul tuo blog o sito puoi usare le varie estensioni che permettono di gestire queste finestre di verifica. Di solito si collocano vicino ai form contatti, nelle landing page o in prossimità dei commenti del blog. Importante, inoltre, prevederli nei moduli d’iscrizione anche per eventi, newsletter, etc… Ecco alcune regole da seguire per i tuoi siti o blog:

  • fai in modo che sia facile per tutti i tuoi potenziali users;
  • prendi in considerazione l’eventualità di possibili problemi di vista e udito;
  • la lingua del captcha deve essere quella dei tuoi utenti;
  • procedi con delle prove tu stesso per "testarli".

Il reCaptcha di Google

Il reCaptcha è plugin messo a disposizione da Google. La sua peculiarità consiste nel fatto che le interpretazioni fornite dagli utenti a caratteri difficili da decifrare per una macchina, contribuiscono alla ottimizzazione della digitalizzazione di testi nelle biblioteche e negli archivi. Negli ultimi anni, Google ha implementato un metodo per riconoscere i bot in maniera più semplice: basta spuntare la casella con scritto "Non sono un robot". This AI system may include a second test in which Internet users have to click on all images containing a certain object.

For some users, captcha codes may seem a bit annoying, especially if they are activated incorrectly. However, it should be considered that their usefulness far outweighs their inconvenience. After all, it's just a matter of wasting a few seconds! Instead, if you own a site, always try to use the benefits of captcha without negatively affecting the user experience, but adding an important level of security for your portal.