What problems will you face when creating a cloud backup service?

Question

Backup

I want to start a cloud backup pet project, but I suppose that it can also be commercialized.

I would like to immediately understand what questions / requests users may have and what problems they will encounter.

The first thing I thought about was encryption of backups.

In order for the user to be sure that the admins cannot decrypt his backups, the data can be decrypted with the user's password. But, it turns out that in this case, when changing the password, all backups need to be re-encrypted? Or is there another solution?

Answer 1

Here is the code of the backup client itself :
https://github.com/restic/restic

Answer 2

Yes, how would you like it? And most importantly, the data needs to be encrypted on the client side, and not on yours.

Answer 3

cloud backup pet project - the first problem is the lack of disk space, for which you will have to pay a lot of money if you want both the place and the speed of connection to the server on the Internet at the level.
that in this case, when changing the password, all backups must be re-encrypted? - this is only half the trouble, firstly, encrypt not with a password, but with a user ID, only so that it does not change when changing the password, login, and so on.
But what happens when the user simply forgets / loses his password or login, or is he stolen and all data deleted????? will you need to make a backup of backups ??? and how many such revisions will need to be done per user??? and how much disk space does it require????
There are a lot of questions, ask how much power Google Drive or Yandex Drive serves, they don't have encryption :)

Answer 4

In order for the user to be sure that the admins cannot decrypt his backups, the data can be decrypted with the user's password.

No.
In this case, the user cannot be sure that the admins cannot decrypt, because they can.
It doesn't matter what password you encrypt with - if you have a password - you can decrypt it.
The user can be sure that you will not decrypt only if he encrypts himself.
Organizers of sites for storing backups generally do not like encryption on the user's side, because this does not allow them to optimize data. For example, the same deduplication can no longer be used.