Emoji CAPTCHA

A CAPTCHA implementation based on identifying emojis

This was exclusively developed to be used in Telegram, but might be used anywhere else.

Brief Description

1. The client sends an HTTP request to the server.

2. The server returns a generated photo that has 6 emojis inside it, along with:

   • A custom header called x-emojis that includes the code points of the six emojis in the photo plus 2 random ones in hex, shuffled, splitted by ";", and the parts of each of them splitted by "-".

   • A custom header called x-correct-emojis that only includes the code points of the 6 emojis in the photo.

3. The client displays the photo returned by the server, along with the emojis provided in the x-emojis in a way the user can pick them.

4. The client compares the first six emojis that the user picked with x-correct-emojis.

Credits

This wouldn't be possible without the inspirations from the CAPTCHA system at @PyrogramLounge.