Encryption

A Qt/SQLite history table encrypts its path columns and matches rows by re-encrypting the paths. The update had three independent faults, each one hiding the next. A store-update-load test found them, and a negative test kept the fix from dropping the match rule.

End-to-end encryption fails when the server is the calculator. Disk encryption still lets the operator read everything. List what the computation needs, then give each reader its own zone and key.

Three takes on storing sensitive data in a database you don't control: AES-256-CTR fields in a desktop app's SQLite, an encrypted payload with an HMAC in MongoDB documents, and a drop-in encrypted text field for SQLAlchemy and Django.