Restricting Access to local PouchDB

问题:

I would like to use PouchDB in a web app desktop client. I work in an environment where the computer user is generic and different persons use the same computer account. However, using my app they must log in with individual user names granting them their corresponding privileges. The system works offline, with period replication to the server.

Browsing through the documentation of PouchDB and searching the Internet I come to understand that there is no access restriction to a local PouchDB. Anyone who has access to the client/browser has in principle access to the cached data. Also implementing any sort of user access control in my web app seems to be kind of pointless. The code could simply be altered to allow access.

I came to the following possible solution and would like to know if that could work:

1. First contact with the central server App sends user credentials to the server. The server encrypts a special databaseKey with the user credentials and sends this encryptedDatabaseKey back to the client app. The client app stores this encryptedDatabaseKey in localStorage, decrypts the contained databaseKey, creates and encrypts the local PouchDB using this databaseKey (e. g. crypto-pouch).
   2. Offline usage User logs into the app, his credentials are used to decrypt the encryptedDatabaseKey in localStorage, only then has he access to the stored data. If someone alters the code of the app he still cannot gain access to the encrypted PouchDB.

I see the following advantages: - Without correct credentials there is no access to the local data - Multiple users can have access to same local PouchDB since the databaseKey is identical. - The databaseKey could even be changed regularly (app compares during a connection to the server the local encryptedDatabaseKey and the one received from the server, if they differ the app decrypts the database using the old key and encrypts it with the new)

Does this seem like a viable solution? Are there any other/better methods of securing a local PouchDB?

回答1:

crypto-pouch is indeed the best method to encrypt a local PouchDB. However, I think where you say

Offline usage User logs into the app, his credentials are used to decrypt the encryptedDatabaseKey in localStorage, only then has he access to the stored data

I think it's pointless to decrypt the key and use that to decrypt the database; you might as well just as the user to create and memorize a password? Then you can use that as the key to the crypto-pouch.