🎁 [Feature Request]: Encrypt the user data and only store the encrypted data on server

[ozgunozerk]

For being user friendly, storing user data on server is helpful, especially for the following cases:

• user switches to another device
• user deletes/reinstalls the app

because, then, the user can still access to their data.

However, since we are storing financial data, some may be uncomfortable with their data is stored on cloud. To help these users, we can utilize symmetric-key encryption.

The only user data the server stores, are the transactions.

So:

1. each client will create a password (this will act as the encryption key)
2. the transactions will be encrypted with the user's password (unknown to server)
3. server will store the encrypted version
4. when client fetches the encrypted version, it can decrypt it with the password

Since the server shouldn't know the password, it cannot store it. Hence, if the user switches to a new device, or deletes/reinstalls the app, the user has to remember the password to access their previous data.

If the user forgets their password, there won't be an alternate way to recover the previous data.

[ozgunozerk]

The UX for this might be challenging, due to:

• probably after logging in, we should have another page for optionally introducing encryption to the user.
• we should explain to the user that why they might or not want the encryption
• we should CLEARLY explain and to the user what will happen if they want to use encryption and they forget their password (DATA WILL BE GONE FOREVER)
  • for sure, there will be some users that will not read the explanations, and proceed with encryption, and then lose their password. And they will be angry when they find out that their previous data is gone

Also, from the technical side:

• determine the state of the art symmetric key encryption algorithm that is also feasible to perform on mobile devices. Because the server won't play any role in encryption/decryption.

[ozgunozerk]

It will be the best to decide whether to add this feature based on the community input and the need of our users.