tricaptcha

Simple and accessible CAPTCHA system that works without Javascript. cap.trimill.xyz.

Environment variables

• RUST_LOG - set log level (default: error)
• TCAP_ADDR - set address (default: localhost:8000)

API

Main page

GET /

• ?count=: number of digits to use in CAPTCHA (clamped between 1 and 16)
• ?userdata=: arbitrary data that will be saved and returned during verification

Submission page

POST /submit

• ?id=: the CAPTCHA ID
• ?digits=: the digits contained in the captcha

Images

GET /image/ID

• ID: the CAPTCHA ID Each image may only be requested once

Audio

GET /audio/ID

• ID: the CAPTCHA ID Each audio may only be requested once

Verification

GET /verify

• ?token=: the CAPTCHA token provided by the user
• HTTP 400 - invalid token
• HTTP 200 - valid token, JSON output:
  • count: number of digits in CAPTCHA
  • issued: time when CAPTCHA was issued to user
  • completed: time when CAPTCHA was completed by user
  • userdata: see above

Dependencies

ffmpeg and imagemagick's convert tool must be installed to generate the images and audio.

Licenses

All original work licensed under the GNU GPLv3.

Digit images are from the MNIST handwritten digits dataset, licensed under the CC BY-SA 3.0 license.

Digit audio are from the FSDD spoken digit dataset v1.0.10, licensed under the CC BY-SA 4.0 license.