robojones / endguard-dart Goto Github PK

The API test is not using all exported functionality. The following aspects are currently missing in the test:

• error handling (using the custom error types)
• state export and import

Ensure that the main module exports the correct datatypes needed. Add a test for this that only uses endguard.dart and native types as imports.

If a message uses a wrong message format, then it cannot be authenticated or decrypted. In the context of this encryption scheme, this should be considered a MessageAuthenticationException. Having a separate exception type for this would complicate the error handling for the library-user. The library is intended to be used more or less like this:

final message = decryptionQueue.pop();
try {
  connection.decrypt(message)
} on MessageAuthenticationException {
  // discard message, do not attempt to decrypt message again
}

Important this should only apply to the parts where we try to parse unauthenticated content. Authenticated content is assumed to have the correct syntax. If not, then that is an implementation error.

The readme needs to be updated to better explain the project

• link to specification
• usage example (warn to read the other sections)
• important security information (correct usage)
  • introduce concept: decryption queue (diagram), error handling
  • handshake (explain what to do with the keys)
  • connection state (importance of persistent storage)

The structure of the code needs improvement and many doc comments are missing.

• Rename the src/encryption directory to src/crypto because "encryption" is overused (e.g. src/connection/encryption.dart) and there will be more crypto functions like a MAC.
• Rename the InitialPackageEncryption class to HandshakeEncryption
• Add doc comments to all exported methods, variables and classes

Support the new features specified in Endguard v0.0.2

https://github.com/robojones/endguard/releases/tag/v0.0.2

• update submodule and generated files
• add ChaCha20-Poly1305 stream cipher
• fix key derivation (should use HKDF instead of a simple hash)
• add secondary MAC with HMAC
• make sure to use the dart doc features in the doc comments

The dependencies need to be kept up-to-date. Dependabot does not yet support Dart packages.

There should be the option to pass additional authenticated data (aad) to the handshake and encrypt/decrypt methods.

The aad could be used in protocols to authenticate the recipient or the server address.

Update all modules to null-safe versions.