Step 3 of ADR 0044 (D3, D18, D19). A shared space's data keys are
sealed on a device to each member's public keys; the instance keeps
what devices sealed and never opens it.
- halkyon_keys: the safety code of two accounts' public keys
(`safetyCode`), 60 digits, the same on both sides.
- halkyon_base: the register hands out accounts' public keys
(`public-keys-of`, local and remote); the table `shared_space_key`
and the endpoint `sharedSpaceKeys` (memberKeys, keysNeeded, seal,
mine). Only the Owner and Editors seal, the first key sealed to a
member stays, and a member's keys go with their membership. Every
host's migration creates the table.
- halkyon_app: `ContentCipher` seals a key to another account and
opens one sealed by another; `SharedKeys` shares a space's key with
its members, seals keys to newcomers and opens the person's own,
holding each member to the public keys `KeyPins` pinned on first
sight (`key_pins.json` in the person's folder), a change refused
until trusted anew.
Learn takes them into its `Privacy` in step 4.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
A day's, night's and heart chunk's ID was a UUID of version 5 of the
person and the date, which the instance can hash for every date itself:
each ID told it which days the band was worn. halkyon_keys' keyedRowId
hashes the name under the account's X25519 secret key (BLAKE2b, a UUID of
version 8), the same on every device of the account and unreadable
without its keys; ContentCipher.rowId and TrainKeys.rowId hand it on.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
The list a recovery phrase's words are of moves from halkyon_keys into
halkyon_core, exported as bip39English, so that the server module can
take a waiting account's matching code from it (Halkyon Learn's ADR
0021, D33) without depending on halkyon_keys and libsodium. Its test
(2048 words, sorted, the published file's SHA-256, unique by their first
four letters) moves along; its MIT licence too.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
A third subkey of the password's Argon2id (context `hlkpass1`, subkey 3)
seeds an Ed25519 pair: `PasswordKeys.proofKeyPair` and `proofPublicKey`.
An account that keeps no SRP verifier proves its password by signing the
register's nonce with it, as it proves the recovery phrase; neither SRP's
verifier nor the unwrapped account keys a signed-in device keeps can make
it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
The reading of the full reading's fixes noted that the main isolate's
copies of SRP's x and the key-encryption key, Dart's own bytes, stayed
for as long as the sign-in sheet's cubit lived, and after every change's
proof.
PasswordUnlock.forget zeroes them: the sign-in cubit wipes what the
password unlocked once signed in, once another password replaced it, and
as it closes; a change's or deletion's proof wipes what it unlocked once
its answer is made. The fake crypto's proof copies its bytes, as a real
one is new bytes. halkyon_keys' README says what is wiped and what isn't.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
Wrapping the account's keys and sealing a data key spread extractBytes()
copies into the buffer libsodium encrypts: the buffer was wiped, the
copies on the way weren't. The keys now go from guarded memory straight
into it (runUnlockedSync), and the seed derived to check a signing key is
disposed. The README said key bytes copied to the Dart heap were wiped
afterwards; it now says exactly which are, and which Dart can't wipe (x as
a BigInt, Strings, what isolates copy, the keyring's base64).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
An instance's salt of another length made the device's cryptography throw
an ArgumentError, a wrapping's nonce a RangeError, and libsodium or the
keyring may throw their own; none was a refusal, so the step's error
escaped and the sheet stayed busy, which can't be closed. halkyon_keys
now checks the lengths of what comes from elsewhere before libsodium sees
it (KeyRefusal.malformed: a salt, a wrapping, a sealed key's box, a sealed
payload), the device's cryptography turns anything else into the general
failure, and so does every password cubit, the error logged by its type
alone.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
Data keys were sealed to the account as anonymous sealed boxes, and the
register knows every account's public key: it could have sealed a key of
its own under an existing key ID, and a device would have encrypted new
content with a key the register holds (the second reading's M7, latent
until step 4 encrypts anything). sealDataKey now signs the box, with the
account it is sealed to and a label, by the sealer's Ed25519 key, and
openDataKey checks that signature against the sealer it expects (the
account itself, or whoever shared the store) before opening anything.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
The register can't check a password it never sees, and should its
database leak, the verifier and the keys wrapped under the password fall
to guessing at Argon2id's cost (the second reading's M8). Devices now
refuse a new password shorter than 12 characters, counted as code points
once normalised (halkyon_keys' checkNewPassword), at sign-up, a reset
keeping the keys and a change alike, before anything is derived; the new
password's field says so, and the refusal has its own text (en, de).
Signing in takes any length, so a password set before keeps working.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
A key proof was a signature by the account's signing key, which every
signed-in device keeps in its keyring: whoever could read one, with a
code from its authenticator, set a new password without the password or
the phrase (the second reading's H1). The phrase now proves itself with
an Ed25519 key derived from its bits alone (halkyon_keys'
recoveryProofKeysOf, KDF context hlkrprf1, a sibling of the recovery
key), whose public half every setup, new phrase and account reset sends
and the register keeps (account_password.recoveryProofKey); the device
derives the secret half only while the phrase is typed. An account
without one (none exist outside development) proves no phrase until it
sets a new one; decoys check against a decoy proof key alike.
Migration (module, Learn's and Todo's servers, Learn's device schema):
ALTER TABLE "account_password" ADD COLUMN "recoveryProofKey" bytea;
nullable, so rows made before keep working and no data is touched.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
PasswordKdf.fromJson refused costs below the floor but took any above it,
so an instance could ask a device for 100 GiB and crash the app at every
sign-in. It now refuses more than the register's own ceiling (16 passes,
1 GiB; KeyRefusal.excessivePasswordKdf), and the app reads either refusal,
before deriving or sending anything, as PasswordProblem.unsafeCosts with
a text of its own (before, costs below the floor read as keys missing).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
ADR 0017, step 3: halkyon_app's side, which Learn and Todo take.
- The account's cryptography on the device (`SodiumAccountCrypto`):
halkyon_keys and SRP's client half, each step on an isolate of its
own. sodium hands out results as views of native memory its
finalizers free once the isolate that made them ends, so everything
crossing back is copied first: a view read freed memory and crashed
the process.
- `PasswordGateway` on the module's endpoints (steps without a session
through a client holding none; an authenticator set up with a session
granted but not yet the device's), and `PasswordRepository` running
the flows: signing in (M2 checked, the keys opened before anything is
trusted), signing up, a password for someone signed in, an account
never finished, the authenticators, recovery codes, changing the
password, a new recovery phrase, and getting back in.
- The unlocked keys in the system's keyring per instance and person
(`SecureAccountKeyStore`), gone once another person signs in or
nobody, and with the instance's removal.
- The screens: the start screen's Sign in and Create an account (and
when GitHub sign-in ends), the sign-in sheet (codes, recovery codes,
an account never finished, a lost authenticator), the account's setup
(the recovery phrase shown once, three random words typed back before
anything reaches the instance; the authenticator's QR code, drawn
with pub.dev's qr; the recovery codes), getting back in, and the
account section (`AccountSecuritySection`).
- `FileSaver` moves from Learn into halkyon_app, for the phrase and the
codes in Todo too; `AppDependencies` names it and `passwords`.
- halkyon_keys rebuilds account keys from the secret keys a device kept;
the key proof's message is in halkyon_base_client, checked against
the register's.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
Other spaces become a plain space and the text is composed (NFC) before
Argon2id, so a password typed on another system, accents composed or
not, unlocks the same keys; empty passwords and control characters are
refused. The normalisation (unorm_dart) is pinned exactly, as it must
never change once an account exists. ADR 0017 records both decisions.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
ADR 0017's step 1, on libsodium (sodium 4.1.0+1, whose build hook
compiles the libsodium 1.0.22 it ships: a C compiler and make wherever
it builds):
- Argon2id (64 MiB, 3 passes, kept with the account and never below
that) makes a master key, which libsodium's KDF splits into SRP's
secret (x) and the key-encryption key.
- The account's X25519 and Ed25519 key pairs, their private halves
wrapped with XChaCha20-Poly1305 under the KEK and under the recovery
key, bound to their public keys.
- A 24-word BIP-39 recovery phrase (the English list, MIT) and the
recovery key derived from it.
- Data keys sealed to the account with crypto_box_seal, bound to their
IDs; content in ADR 0002's envelope, encrypted with a data key and
signed with Ed25519 (detached), bound to a context the caller names.
- Secrets in libsodium's guarded memory where its API takes them.
- Tests: libsodium's Argon2id known answers, BIP-39's English vectors,
round trips and every refusal.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
