Add compatibility test for encryption (second pass)

[eerxuan]

Part of #52.

Category: system / security

Add compatibility test coverage for the encryption feature.

Note: a smoke test exists; comprehensive compatibility test coverage is needed.

[RyanGarfinkel]

Hi! I'm a student in the CodePath AI301 program and I'd like to work on this issue. I'll start by getting the existing comparability tests to run, expanding the suite for encryption, then open a PR. Any pointers on where to start in the codebase would be appreciated!