c1ce262f3e
A group can make another group, and the child can prove where it came from. This
is the plan for that, in nine phases, written against the code at b50b1762 and
not yet built.
**A subgroup is an ordinary robust group plus one artefact.** Fresh ChillDKG key,
fresh room, fresh quorum, and a birth certificate -- the parent's signature over
the child's room id -- carried on the child's `GroupKeyState`. Deriving the child
at `m/9420/1/0` instead would cost no ceremony at all and was rejected: a derived
child is the parent wearing a different hat, administered by the parent's members
with the parent's quorum, when the whole point is that a different set of people
can act on their own. The certificate is a claim about lineage, never a
delegation of authority, and nothing here lets one group sign for the other.
**Four steps, in the only order they can happen.** The ceremony produces `K`, so
the child's id exists; the parent's quorum certifies that id; the child's quorum
signs a key state carrying the certificate; the coordinator creates the room. No
step is a policy choice -- each needs the one before it -- and the last is gated
on the key state for the same reason `createAdminGroup` already is.
**What the parent's admins actually sign is the argument that shaped the event.**
Taken literally the certificate is 32 opaque bytes produced by a ceremony most of
them were not in. So the content is exactly the new group id as specified, and
the tags carry the child's threshold key, the path and the admin set -- covered
by the same signature, since an id hashes over its tags -- which lets a signer's
device check `marmotGroupId(key, path) == content` before agreeing, and lets a
coordinator who lies about who is in the child do it in a field the parent's
signature covers.
**The whole certificate travels as JSON on the key state, not a bare signature.**
A signature plus a rule for rebuilding the event it covers is a rule that breaks
silently the first time the event's shape changes: a rebuild differing by one
byte hashes to an id whose signature fails, and is indistinguishable from a
forgery. A parent tag rides beside it as an index into the certificate rather
than a second source of truth -- Phase 3 drops any state carrying one without the
other, or the two disagreeing, so there is no state where the index is believed
and the certificate is not.
**The ceremony stays on gift wraps, and the reason is `mls-skipped-keys.md`.**
Holding all three steps in the parent's Marmot room is the better design and the
plan says so at length rather than dismissing it: the certificate already runs
there, and the key state and the ceremony move together or not at all, since both
`GroupKeyStateManager.propose` and `signingPath` tie a key state to the room its
ceremony ran in. The mechanical cost is three enumerable changes. The reason to
wait is that the skipped-keys note already lists `proposeRitual` as a reliable
trigger, and a DKG cannot finish without every participant -- so one message
dropped for good stalls it permanently, where FROST needs `t` of `n` and routes
around a lost nonce. Revisit when the quartz fix lands; the collision Phase 4
refuses disappears with it.
**Three admins in total, and the threshold is set before anything is published.**
Three is `ChatRoomType.MINIMUM_ROBUST_GROUP_SIZE` for the reason that constant
gives, and the coordinator counts because they hold a share by construction, so
the picker asks for two others. `t` has to be chosen on that same screen and
nowhere later: ChillDKG hashes it and the host keys into the session identity, so
it is fixed the moment the proposal goes out, and a group that disagrees about it
gets no key rather than a weak one.
The nine phases are ordered so the checkable parts come first and can ship dark:
the certificate and its verifier are pure, the schema is three nullable columns,
and nothing produces a certificate until the button in Phase 7 exists. Phase 6
extracts the 120 lines of Marmot room creation out of `DkgRitualViewModel` so
both flows share the rules that are already right there.
What it does not do is named rather than left to be found: no revocation, no
delegation, certificates are not chroniclable, one subgroup per admin set, and
every selected admin has to show up twice.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This is a Kotlin Multiplatform project targeting Android, iOS, Desktop (JVM).
-
/composeApp is for code that will be shared across your Compose Multiplatform applications. It contains several subfolders:
- commonMain is for code that’s common for all targets.
- Other folders are for Kotlin code that will be compiled for only the platform indicated in the folder name. For example, if you want to use Apple’s CoreCrypto for the iOS part of your Kotlin app, the iosMain folder would be the right place for such calls. Similarly, if you want to edit the Desktop (JVM) specific part, the jvmMain folder is the appropriate location.
-
/iosApp contains iOS applications. Even if you’re sharing your UI with Compose Multiplatform, you need this entry point for your iOS app. This is also where you should add SwiftUI code for your project.
Build and Run Android Application
To build and run the development version of the Android app, use the run configuration from the run widget in your IDE’s toolbar or build it directly from the terminal:
- on macOS/Linux
./gradlew :composeApp:assembleDebug - on Windows
.\gradlew.bat :composeApp:assembleDebug
Build and Run Desktop (JVM) Application
To build and run the development version of the desktop app, use the run configuration from the run widget in your IDE’s toolbar or run it directly from the terminal:
- on macOS/Linux
./gradlew :composeApp:run - on Windows
.\gradlew.bat :composeApp:run
Build and Run iOS Application
To build and run the development version of the iOS app, use the run configuration from the run widget in your IDE’s toolbar or open the /iosApp directory in Xcode and run it from there.
Learn more about Kotlin Multiplatform…