Implement zk-snarks email verification within Layer8

[interestIngc]

The goal of this issue is to:

• Implement user's email verification.
  • Send out the generated verification code onto user's email address. This code should be persisted in a database with a predefined TTL. I suggest using the MailerSend API to send out verification codes, they provide a free plan of 100 emails / day which is enough at this stage for our purposes. The overall verification flow should be insensitive to the selected email-sending provider though.
  • Implement user's redirection to another web page after clicking the "verify email" button. This web page should contain a field to enter the verification code as well as a "submit" button to trigger a new API endpoint.
  • Implement a new API endpoint to verify the code submitted by user at the previous step by matching it to the generated verification code fetched from the database.
  • Notify a user with either success, or failure outcome and update user's verification status at the database.
• Implement zk-proofs of the conducted email verification procedure.
  • Use the hash function to generate a verification code from the user's email and/or potentially other user's data. I suggest using the Polynomial Rolling Hash.
  • Generate a zk-proof of running the code generator procedure using the groth16 protocol and the gnark zk-snarks library.
  • Persist the verification code and the zk-proof at the database instead of the actual email.

[stravid87]

July 6, 2024 Next Steps

• [x] Integrate into the main flow
• [x] Write unit test coverage
• [x] Modify the database schema

[stravid87]

July 13, 2024 Next Steps

• [x] Write unit test coverage
• [x] Bugs as per Kanban board
• [ ] Research DIDs. Should we write to the sovrin network? And if not, is there another blockchain DID project we should?
• [ ] Research hyperledger to see if there is any opportunities for ongoing development for us?