MCaptcha

lastmod 2022-08-11created 2022-08-113 edits

A no-nonsense CAPTCHA system with seamless UX | Backend component

A free, open-source CAPTCHA based on PoW

Features

• Uses SHA256-based PoW (Proof of Work)
• Makes the computer do the work, so the person doesn't have to select images or spend time
  • To make a request to the server, you generate and send a PoW, and a token is issued
  • You then include that token in your request, and it is processed after verification
• Completely invisible from the user's point of view
• Privacy protection (no cookies, independent of IP address)
• Resistant to replay attacks: a PoW is usable only for a short time and only once
• Legitimate users see almost no delay; under attack there may be a delay of about 2 seconds or less

See also

• Captcha
• Proof of work

Favorite site

• Github - mCaptcha