Encryption

How does Passwords implement CSE/E2E

Passwords uses Libsodium to encrypt and decrypt user data. Implementations of Libsodium are available for many different programming languages and usually provide a very similar api. The library also provides good performance and security while being comparably easy to use. E2E in Passwords is designed to be upgradeable which is why every part of it is implemented separately and has its own version information.

Encryption and Token types

Password challenge

Type	Description
PWDv1r1	The standard master password challenge

Keychains

Type	Description
CSEv1r1	The standard CSE keychain

CSE/E2E encryption

Type	Description
none	An object without any client side encryption. Only available with SSE other than none
CSEv1r1	The standard CSE encryption

SSE encryption

Type	Description
none	An object without any server side encryption. Only available with CSE other than none
SSEv1r1	An object with first generation server side encryption. Uses a server key, user key and object key
SSEv1r2	An object with second generation server side encryption. Uses the Nextcloud secret, user key and object key
SSEv2r1	An object with secure server side encryption. SSEv2 uses a keychain which is remporarily decrypted with the challenge secret

2FA token

Type	Description
user-token	A token where the user has to enter a code
request-token	A token where a second device or app is used for confirmation

Graphical schema of the encryption flow

sequenceDiagram
    participant User
    participant Client
    participant Server
    loop Authentication
        User->>Client: Requests login
        Client->>Server: Requests session
        Server->>Client: Challenge / Token
        Client->>User: Requests password / token
        User->>Client: Provides password / token
        Client->>Client: Solves challenge
        Client->>Server: Challenge solution / token
        Server->>Server: Validates challenge / token
        Server->>Client: Sends Keychain
    end
   Client->>Client: Decrypt keychain
   Client->>Client: Initialize encryption
   Client->>User: Report login success
   loop Object decryption
        Client->>Server: Requests objects
        Server->>Client: Sends objects
        Client->>Client: Decrypts objects
        Client->>User: Shows objects
    end
   loop Object encryption
        User->>Client: Changes objects
        Client->>Client: Encrypts objects
        Client->>Server: Sends objects
        Server->>Client: Confirms changes
        Client->>User: Shows changes
    end

Loading