Feature Request: Secure Account Merger account or family linked account.

[Baximus855]

I’d like to request a feature to securely merge two Ente accounts into one.

Use Case:
A user inadvertently creates a second account (e.g., using a different email alias) and starts building a photo library there, while their main subscription plan remains active on a primary account. The user wishes to consolidate their paid subscription and all associated photo libraries under a single account without losing any data or relying on temporary workarounds like shared albums.

Proposed Solution:
Implement a secure, user-driven merge process that respects Ente’s end-to-end encryption. The process could function as follows:

1. Initiation: A logged-in user initiates a "Merge Account" feature from within the settings of their primary account.
2. Verification: The user is prompted to log in to the secondary account they wish to merge, proving ownership of both accounts.
3. Key Verification: The application verifies that the user has access to the encryption keys for both accounts (by decrypting a small test piece of data from each).
4. Local Decryption & Re-encryption: On the user's trusted device, the app securely downloads, decrypts, and then re-encrypts all data from the secondary account using the primary account's masterKey.
5. Upload: The re-encrypted data is uploaded to the primary account's storage on Ente's servers.
6. Cleanup: The secondary account and its original encrypted data are permanently deleted from the server.

This process ensures Ente's servers never see unencrypted data or any user encryption keys, preserving the zero-knowledge architecture. The heavy lifting is done locally on the user's device, which aligns with the secure principles of end-to-end encryption.

Even a well managed share risks leaving gaps; a month from now, you may realize a crucial photo wasn't included in that transfer, and because the original account has been deleted, that data is gone forever. This is why an account merger is the only complete solution.