electron/docs/api/safe-storage.md
Samuel Attard b31acfb706
docs: clarify security semantics of safeStorage (#42666)
* docs: clarify security semantics of safeStorage

* Apply suggestions from code review

Co-authored-by: Erick Zhao <erick@hotmail.ca>

* Update safe-storage.md

* Update safe-storage.md

---------

Co-authored-by: Erick Zhao <erick@hotmail.ca>
2024-06-26 13:24:06 -07:00

4.1 KiB

safeStorage

Allows access to simple encryption and decryption of strings for storage on the local machine.

Process: Main

This module adds extra protection to data being stored on disk by using OS-provided cryptography systems. Current security semantics for each platform are outlined below.

  • macOS: Encryption keys are stored for your app in Keychain Access in a way that prevents other applications from loading them without user override. Therefore, content is protected from other users and other apps running in the same userspace.
  • Windows: Encryption keys are generated via DPAPI. As per the Windows documentation: "Typically, only a user with the same logon credential as the user who encrypted the data can typically decrypt the data". Therefore, content is protected from other users on the same machine, but not from other apps running in the same userspace.
  • Linux: Encryption keys are generated and stored in a secret store that varies depending on your window manager and system setup. Options currently supported are kwallet, kwallet5, kwallet6 and gnome-libsecret, but more may be available in future versions of Electron. As such, the security semantics of content protected via the safeStorage API vary between window managers and secret stores.
    • Note that not all Linux setups have an available secret store. If no secret store is available, items stored in using the safeStorage API will be unprotected as they are encrypted via hardcoded plaintext password. You can detect when this happens when safeStorage.getSelectedStorageBackend() returns basic_text.

Note that on Mac, access to the system Keychain is required and these calls can block the current thread to collect user input. The same is true for Linux, if a password management tool is available.

Methods

The safeStorage module has the following methods:

safeStorage.isEncryptionAvailable()

Returns boolean - Whether encryption is available.

On Linux, returns true if the app has emitted the ready event and the secret key is available. On MacOS, returns true if Keychain is available. On Windows, returns true once the app has emitted the ready event.

safeStorage.encryptString(plainText)

  • plainText string

Returns Buffer - An array of bytes representing the encrypted string.

This function will throw an error if encryption fails.

safeStorage.decryptString(encrypted)

  • encrypted Buffer

Returns string - the decrypted string. Decrypts the encrypted buffer obtained with safeStorage.encryptString back into a string.

This function will throw an error if decryption fails.

safeStorage.setUsePlainTextEncryption(usePlainText)

  • usePlainText boolean

This function on Linux will force the module to use an in memory password for creating symmetric key that is used for encrypt/decrypt functions when a valid OS password manager cannot be determined for the current active desktop environment. This function is a no-op on Windows and MacOS.

safeStorage.getSelectedStorageBackend() Linux

Returns string - User friendly name of the password manager selected on Linux.

This function will return one of the following values:

  • basic_text - When the desktop environment is not recognised or if the following command line flag is provided --password-store="basic".
  • gnome_libsecret - When the desktop environment is X-Cinnamon, Deepin, GNOME, Pantheon, XFCE, UKUI, unity or if the following command line flag is provided --password-store="gnome-libsecret".
  • kwallet - When the desktop session is kde4 or if the following command line flag is provided --password-store="kwallet".
  • kwallet5 - When the desktop session is kde5 or if the following command line flag is provided --password-store="kwallet5".
  • kwallet6 - When the desktop session is kde6.
  • unknown - When the function is called before app has emitted the ready event.