{"id":1294,"date":"2014-08-28T23:45:44","date_gmt":"2014-08-28T22:45:44","guid":{"rendered":"https:\/\/seed4.me\/blog\/?p=1294"},"modified":"2014-08-28T23:46:39","modified_gmt":"2014-08-28T22:46:39","slug":"why-is-captcha-used-for-security","status":"publish","type":"post","link":"https:\/\/alexahub.net\/blog\/why-is-captcha-used-for-security\/","title":{"rendered":"Why is CAPTCHA used for security?"},"content":{"rendered":"<p><span id=\"__w2_mxUdLNi_toggle_link\"><span id=\"ld_sqtekm_45159\"><span id=\"ld_sqtekm_45160\"><span class=\"inline_editor_value\"><span id=\"__w2_mxUdLNi_toggle_link\"><span id=\"ld_sqtekm_45159\"><span id=\"ld_sqtekm_45160\"><span class=\"inline_editor_value\">A CAPTCHA is something that is designed to tell a human and robot apart. It does it by posing a problem which is easy for human but difficult for computers. For example, extracting text from randomly distorted image. Takes (a few seconds for) a dumb human to solve, but very sophisticated AI engine for the same problem, that too with limited accuracy.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<img loading=\"lazy\" decoding=\"async\" width=\"567\" height=\"227\" class=\"alignnone size-full wp-image-1296\" src=\"\/blog\/wp-content\/uploads\/2014\/08\/captcha-basic.jpg\" alt=\"captcha\" srcset=\"https:\/\/alexahub.net\/blog\/wp-content\/uploads\/2014\/08\/captcha-basic.jpg 567w, https:\/\/alexahub.net\/blog\/wp-content\/uploads\/2014\/08\/captcha-basic-300x120.jpg 300w, https:\/\/alexahub.net\/blog\/wp-content\/uploads\/2014\/08\/captcha-basic-374x150.jpg 374w\" sizes=\"(max-width: 567px) 100vw, 567px\" \/>\n<p>But, computers are millions times faster to do rest of the boring work, for example filling up a form in a html page and submit it. Humans probably needs 30 seconds to fill one, where a automated bot can submit several 1000 per second.<\/p>\n<p>Now you setup a service that&#8217;s human consumable, but open to abuse by bots. Most popular example is register a new user in your site (bots will do so in massive scale, use them to spam and abandon them). This abuse will probably deny legitimate users a service, and hence your service will be under DoS (denial of service) attack.<\/p>\n<p>A CAPTCHA will keep such automated bots away (at the cost of adding a few seconds to human annoyance), and hence\u00a0 improve the security of your service (prevents DoS\/flooding by bots).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A CAPTCHA is something that is designed to tell a human and robot apart. It does it by posing a problem which is easy for human but difficult for computers. For example, extracting text from randomly distorted image. Takes (a few seconds for) a dumb human to solve, but very sophisticated AI engine for the&#8230;  <a href=\"https:\/\/alexahub.net\/blog\/why-is-captcha-used-for-security\/\" class=\"more-link\" title=\"Read Why is CAPTCHA used for security?\">Read more &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,9],"tags":[72,38,5],"_links":{"self":[{"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/posts\/1294"}],"collection":[{"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/comments?post=1294"}],"version-history":[{"count":2,"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/posts\/1294\/revisions"}],"predecessor-version":[{"id":1297,"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/posts\/1294\/revisions\/1297"}],"wp:attachment":[{"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/media?parent=1294"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/categories?post=1294"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alexahub.net\/blog\/wp-json\/wp\/v2\/tags?post=1294"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}