- `ContentKeys` opens the person's data keys (`content_key`) with their
account's keys on the device, an anonymous person's device keys made as
their data first opens; it makes a private studyset's key and the
personal key. Without the account's keys nothing opens and nothing new
is private (D8).
- `PayloadEnvelope` is the one place payloads are sealed and opened, each
for its table, row and column, so a payload moved to another row never
opens; one that doesn't open is `Locked`, never half-read.
- `Privacy` gives each gateway the key of the row's tree (its top-level
studyset's), and rewrites a tree under another key, or readable, in
place (`rekeyTree`).
- The studyset, card, note, learning path, path answer and PDF gateways
seal with their tree's key and open what they read: a new top-level
studyset is private where the device holds the keys, a new one inside a
tree takes its privacy, and one moved into another tree is rewritten
under that tree's key. Tags and settings are sealed with the personal
key; a tag or settings row that doesn't open here is left out, so
nothing folds or deletes it. A studyset whose key doesn't open shows as
locked (`Studyset.isLocked`); other rows that don't open read as blank.
- Every payload codec round-trips sealed, and refuses another row.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
`ContentCipher` makes a person's data keys, sealed to their account and
signed by it, opens them, and seals and opens a row's content with them for
the row it is stored in (`SodiumContentCipher`, on the isolate it is used
on, as rows are read and written one by one; `FakeContentCipher` for
tests). A sealed payload holds the signature, then the ciphertext.
`AccountCrypto.newDeviceKeys` makes the key pairs an anonymous person's
device encrypts their private studysets with (ADR 0017, point 9, not built
before); setting a password keeps them as the account's
(`keepingKeys` with a new phrase), so nothing they made private is lost.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
