I’m creating a admin web site, first step is login, There have a captcha option in the login page, How to create a captcha code in phoenix? I mean its like php can generate the captcha picture url, and use session to save and validate it.
What about using something like recaptcha?
Much easier and most likely much more effective than implementing your own.
Yeah do not try to recreate a captcha, they are more easily read by bots than humans nowadays. If you want to do something yourself that have the login person answer a set of questions that only those in that community should know (not something like 2+4, also easily done by bots). However reCaptcha as @AstonJ said is definitely one of the best, especially if you use the most updated API’s for it.