fix(auth)!: proofs are bound to the instance the device addresses

Nothing tied a sign-in's proof to the instance it was made for: an
instance a person was lured into adding could pass A, M1 and the code on
to the real register and get a session there, and pass a phrase's proof
on with a password of its own in place of the person's (the second
reading's M6). SRP's identity is now a label, the challenge's ID and
the host the device addressed (passwordIdentity, in halkyon_base_client
and halkyon_base_server alike), and the phrase's proof signs that host,
what it is for (an authenticator's reset or a new password) and the new
password's digest (key proof v2). Every proving call carries the host;
in production it must be the server's apiServer.publicHost (otherwise
otherInstance, which the app shows as an instance it can't trust), in
development any; a member forwards its own. The tests prove that a
relayed sign-in, a proof for another host or purpose, and a swapped
password are refused, nothing changing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

packages/halkyon_base_server/lib/base.dart

@@ -25,7 +25,8 @@ export 'src/password/authenticators.dart'
         forgetUnconfirmedAuthenticators,
         maxAuthenticators,
         unconfirmedAuthenticatorLifetime;
-export 'src/password/key_proof.dart' show keyProofMessage;
+export 'src/password/key_proof.dart'
+    show KeyProofPurpose, keyProofMessage, newPasswordDigest, passwordIdentity;
 export 'src/password/password_config.dart';
 export 'src/password/passwords.dart'
     show

packages/halkyon_base_server/lib/src/generated/endpoints.dart

@@ -339,6 +339,11 @@ class Endpoints extends _is.EndpointDispatch {
               type: _is.getType<_idt.ByteData?>(),
               nullable: true,
             ),
+            'host': _is.ParameterDescription(
+              name: 'host',
+              type: _is.getType<String>(),
+              nullable: false,
+            ),
           },
           call:
               (
@@ -358,6 +363,7 @@ class Endpoints extends _is.EndpointDispatch {
                         code: params['code'],
                         keyChallenge: params['keyChallenge'],
                         signature: params['signature'],
+                        host: params['host'],
                       ),
         ),
         'beginKeyProof': _is.MethodConnector(
@@ -409,6 +415,11 @@ class Endpoints extends _is.EndpointDispatch {
               type: _is.getType<String?>(),
               nullable: true,
             ),
+            'host': _is.ParameterDescription(
+              name: 'host',
+              type: _is.getType<String>(),
+              nullable: false,
+            ),
           },
           call:
               (
@@ -424,6 +435,7 @@ class Endpoints extends _is.EndpointDispatch {
                         password: params['password'],
                         totpCode: params['totpCode'],
                         recoveryCode: params['recoveryCode'],
+                        host: params['host'],
                       ),
         ),
         'startAccountReset': _is.MethodConnector(
@@ -710,6 +722,11 @@ class Endpoints extends _is.EndpointDispatch {
               type: _is.getType<_ijye8mcv.NewPassword>(),
               nullable: false,
             ),
+            'host': _is.ParameterDescription(
+              name: 'host',
+              type: _is.getType<String>(),
+              nullable: false,
+            ),
           },
           call:
               (
@@ -724,6 +741,7 @@ class Endpoints extends _is.EndpointDispatch {
                     totpCode: params['totpCode'],
                     recoveryCode: params['recoveryCode'],
                     password: params['password'],
+                    host: params['host'],
                   ),
         ),
         'setRecoveryKeys': _is.MethodConnector(
@@ -764,6 +782,11 @@ class Endpoints extends _is.EndpointDispatch {
               type: _is.getType<_idt.ByteData>(),
               nullable: false,
             ),
+            'host': _is.ParameterDescription(
+              name: 'host',
+              type: _is.getType<String>(),
+              nullable: false,
+            ),
           },
           call:
               (
@@ -779,6 +802,7 @@ class Endpoints extends _is.EndpointDispatch {
                     recoveryCode: params['recoveryCode'],
                     recoveryKeys: params['recoveryKeys'],
                     recoveryProofKey: params['recoveryProofKey'],
+                    host: params['host'],
                   ),
         ),
       },
@@ -846,6 +870,11 @@ class Endpoints extends _is.EndpointDispatch {
               type: _is.getType<String?>(),
               nullable: true,
             ),
+            'host': _is.ParameterDescription(
+              name: 'host',
+              type: _is.getType<String>(),
+              nullable: false,
+            ),
           },
           call:
               (
@@ -863,6 +892,7 @@ class Endpoints extends _is.EndpointDispatch {
                         recoveryCode: params['recoveryCode'],
                         request: params['request'],
                         code: params['code'],
+                        host: params['host'],
                       ),
         ),
         'signUp': _is.MethodConnector(

packages/halkyon_base_server/lib/src/generated/password/password_refusal.dart

@@ -73,7 +73,12 @@ enum PasswordRefusal implements _is.SerializableModel {
   /// Adding an authenticator to an account that has one confirmed takes a
   /// code from one of those, which is missing or isn't right: a session
   /// alone adds no second factor.
-  wrongExistingCode;
+  wrongExistingCode,
+
+  /// The device addressed this instance by another name than its own
+  /// (`apiServer.publicHost`): what it proves is bound to the name it
+  /// addressed, so the operator must configure the name devices use.
+  otherInstance;
 
   static PasswordRefusal fromJson(String name) {
     switch (name) {
@@ -111,6 +116,8 @@ enum PasswordRefusal implements _is.SerializableModel {
         return PasswordRefusal.noReset;
       case 'wrongExistingCode':
         return PasswordRefusal.wrongExistingCode;
+      case 'otherInstance':
+        return PasswordRefusal.otherInstance;
       default:
         throw ArgumentError(
           'Value "$name" cannot be converted to "PasswordRefusal"',

packages/halkyon_base_server/lib/src/password/account_recovery.dart

@@ -3,6 +3,7 @@ import 'dart:typed_data';
 import 'package:clock/clock.dart';
 import 'package:halkyon_base_server/src/auth/email.dart';
 import 'package:halkyon_base_server/src/generated/protocol.dart';
+import 'package:halkyon_base_server/src/password/key_proof.dart';
 import 'package:halkyon_base_server/src/password/passwords.dart';
 import 'package:halkyon_base_server/src/register/sessions_ended.dart';
 import 'package:serverpod/serverpod.dart';
@@ -50,6 +51,7 @@ Future<ResetPending> resetAuthenticator(
   String? code,
   UuidValue? keyChallenge,
   ByteData? signature,
+  required String host,
 }) async {
   final pod = session.serverpod;
   final keys = requirePasswordKeys(pod);
@@ -59,6 +61,7 @@ Future<ResetPending> resetAuthenticator(
     challenge: challenge,
     clientValue: clientValue,
     clientProof: clientProof,
+    host: host,
   );
   final to = normalizedAddress(address);
   if (to == null || addressHash(pod, to) != proved.addressHash) {
@@ -80,6 +83,8 @@ Future<ResetPending> resetAuthenticator(
       keys,
       challenge: keyChallenge,
       signature: signature,
+      host: host,
+      purpose: KeyProofPurpose.authenticatorReset,
     );
     if (owner.authUserId != account) {
       throw refusedFor(PasswordRefusal.wrongCredentials);
@@ -117,6 +122,7 @@ Future<AccountSessionsEnded> resetPasswordWithPhrase(
   required NewPassword password,
   String? totpCode,
   String? recoveryCode,
+  required String host,
 }) async {
   final keys = requirePasswordKeys(session.serverpod);
   if (!isNewPassword(password)) {
@@ -127,6 +133,9 @@ Future<AccountSessionsEnded> resetPasswordWithPhrase(
     keys,
     challenge: challenge,
     signature: signature,
+    host: host,
+    purpose: KeyProofPurpose.passwordReset,
+    digest: newPasswordDigest(password),
   );
   final account = row.authUserId;
   await secondFactor(

packages/halkyon_base_server/lib/src/password/account_recovery_endpoint.dart

@@ -2,6 +2,7 @@ import 'dart:typed_data';
 
 import 'package:halkyon_base_server/src/common/network.dart';
 import 'package:halkyon_base_server/src/generated/protocol.dart';
+import 'package:halkyon_base_server/src/password/key_proof.dart';
 import 'package:halkyon_base_server/src/password/passwords.dart';
 import 'package:halkyon_base_server/src/register/account_register.dart';
 import 'package:halkyon_base_server/src/register/people.dart';
@@ -30,6 +31,7 @@ class AccountRecoveryEndpoint extends Endpoint {
     String? code,
     UuidValue? keyChallenge,
     ByteData? signature,
+    required String host,
   }) => AccountRegister.of(session.serverpod).resetAuthenticator(
     session,
     challenge: challenge,
@@ -41,6 +43,7 @@ class AccountRecoveryEndpoint extends Endpoint {
     code: code,
     keyChallenge: keyChallenge,
     signature: signature,
+    host: deviceHostOn(session.serverpod, host),
   );
 
   /// The first step of proving the recovery phrase for [address]: the
@@ -64,6 +67,7 @@ class AccountRecoveryEndpoint extends Endpoint {
     required NewPassword password,
     String? totpCode,
     String? recoveryCode,
+    required String host,
   }) async {
     final ended = await AccountRegister.of(session.serverpod)
         .resetPasswordWithPhrase(
@@ -73,6 +77,7 @@ class AccountRecoveryEndpoint extends Endpoint {
           password: password,
           totpCode: totpCode,
           recoveryCode: recoveryCode,
+          host: deviceHostOn(session.serverpod, host),
         );
     return await issueSessionAfter(
       session,

packages/halkyon_base_server/lib/src/password/key_proof.dart

@@ -1,25 +1,125 @@
 import 'dart:convert';
 import 'dart:typed_data';
 
+import 'package:crypto/crypto.dart' as hashes;
 import 'package:cryptography/cryptography.dart';
+import 'package:halkyon_base_server/src/generated/protocol.dart';
 import 'package:serverpod/serverpod.dart';
 
-// Proving the recovery phrase (ADR 0017): the device opens the account's
-// private keys with the phrase and signs, with the Ed25519 key so opened,
-// what [keyProofMessage] makes of the register's challenge; the register
-// checks the signature against the account's public signing key. Only the
-// account's own key signs so: the phrase never leaves the device.
+// What a device proves and signs, bound to the instance it addresses (ADR
+// 0017; the second reading's M6): SRP's identity and the recovery phrase's
+// proof carry the host the device addressed, so a hostile instance a person
+// was lured into adding can't relay them to the real one, which takes them
+// only for its own host; and a phrase's proof for a new password signs that
+// password, so nobody between can swap in another. The phrase's proof key
+// is the phrase's own (`recoveryProofKey`), never the account's signing key.
+// halkyon_base_client's `key_proof.dart` makes the same bytes.
 
-/// What the device signs to prove the recovery phrase: a label naming the
-/// purpose and its version, the challenge's ID (its 16 bytes) and its nonce,
-/// so a signature made for one challenge, or for anything else the account
-/// signs, never counts for another.
-Uint8List keyProofMessage(UuidValue challenge, List<int> nonce) =>
-    Uint8List.fromList([
-      ...utf8.encode('halkyon key proof v1|'),
-      ...challenge.toBytes(),
-      ...nonce,
-    ]);
+/// SRP's identity I for the sign-in [challenge] on [host] (in lower case):
+/// x comes from Argon2id over the password and salt alone, so I only binds
+/// the proof, to this sign-in and this instance.
+Uint8List passwordIdentity(UuidValue challenge, String host) => _framed([
+  utf8.encode('halkyon srp identity v1'),
+  challenge.toBytes(),
+  utf8.encode(host.toLowerCase()),
+]);
+
+/// What proving the recovery phrase is for.
+enum KeyProofPurpose {
+  /// Asking for the reset of a lost authenticator.
+  authenticatorReset('authenticator reset'),
+
+  /// Setting a new password, the keys staying.
+  passwordReset('password reset');
+
+  KeyProofPurpose(this.label);
+
+  /// The words the message carries.
+  final String label;
+}
+
+/// What the device signs with the phrase's proof key: a label naming the
+/// format, the challenge's ID (its 16 bytes), its nonce, the [host] the
+/// device addressed, the [purpose] and the [digest] of what it sets
+/// ([newPasswordDigest]), each framed by its length; so a signature made
+/// for one challenge, instance, purpose or password never counts for
+/// another.
+Uint8List keyProofMessage(
+  UuidValue challenge,
+  List<int> nonce, {
+  required String host,
+  required KeyProofPurpose purpose,
+  List<int> digest = const [],
+}) => _framed([
+  utf8.encode('halkyon key proof v2'),
+  challenge.toBytes(),
+  nonce,
+  utf8.encode(host.toLowerCase()),
+  utf8.encode(purpose.label),
+  digest,
+]);
+
+/// The SHA-256 of [password] as the device sent it, framed: what a
+/// phrase's proof for it signs.
+Uint8List newPasswordDigest(NewPassword password) => Uint8List.fromList(
+  hashes.sha256
+      .convert(
+        _framed([
+          utf8.encode('halkyon new password v1'),
+          Uint8List.sublistView(password.salt),
+          utf8.encode(password.costs.algorithm),
+          utf8.encode('${password.costs.opsLimit}'),
+          utf8.encode('${password.costs.memLimit}'),
+          Uint8List.sublistView(password.verifier),
+          Uint8List.sublistView(password.passwordKeys.nonce),
+          Uint8List.sublistView(password.passwordKeys.cipherText),
+        ]),
+      )
+      .bytes,
+);
+
+/// [parts], each after its length in four bytes, big-endian.
+Uint8List _framed(List<List<int>> parts) {
+  final bytes = BytesBuilder(copy: false);
+  for (final part in parts) {
+    bytes
+      ..addByte((part.length >> 24) & 0xff)
+      ..addByte((part.length >> 16) & 0xff)
+      ..addByte((part.length >> 8) & 0xff)
+      ..addByte(part.length & 0xff)
+      ..add(part);
+  }
+  return bytes.takeBytes();
+}
+
+/// The host a device addressed this server by ([claimed]), which its proofs
+/// are bound to: where the server runs for real, only its own public host
+/// ([publicHost], `apiServer.publicHost`), refused otherwise
+/// ([PasswordRefusal.otherInstance]: the instance is configured under
+/// another name than the device reaches it by); in development whatever
+/// the device names, as an emulator reaches the developer's machine as
+/// 10.0.2.2 and a phone on the network by its address. A relaying
+/// instance gains nothing either way: the device's proof names the host it
+/// addressed, and the real one checks it for its own.
+String deviceHost({
+  required String runMode,
+  required String publicHost,
+  required String claimed,
+}) {
+  final host = claimed.trim().toLowerCase();
+  if (runMode != ServerpodRunMode.development &&
+      host != publicHost.trim().toLowerCase()) {
+    throw PasswordRefusedException(reason: PasswordRefusal.otherInstance);
+  }
+  return host;
+}
+
+/// [deviceHost] on [pod].
+String deviceHostOn(Serverpod pod, String claimed) => deviceHost(
+  runMode: pod.runMode,
+  publicHost: pod.config.apiServer.publicHost,
+  claimed: claimed,
+);
 
 /// Whether [signature] is the account's Ed25519 signature ([publicKey], 32
 /// bytes) over [message]; false for anything malformed.

packages/halkyon_base_server/lib/src/password/password_change.dart

@@ -36,6 +36,7 @@ Future<void> changePassword(
   required ByteData clientProof,
   String? totpCode,
   String? recoveryCode,
+  required String host,
   required NewPassword password,
   UuidValue? keepSession,
 }) async {
@@ -52,6 +53,7 @@ Future<void> changePassword(
     clientProof: clientProof,
     totpCode: totpCode,
     recoveryCode: recoveryCode,
+    host: host,
   );
   await session.db.transaction((transaction) async {
     // UPDATE "account_password" SET "salt" = $1, "kdfAlgorithm" = $2,
@@ -101,6 +103,7 @@ Future<void> setRecoveryKeys(
   required ByteData clientProof,
   String? totpCode,
   String? recoveryCode,
+  required String host,
   required WrappedKeys recoveryKeys,
   required ByteData recoveryProofKey,
 }) async {
@@ -117,6 +120,7 @@ Future<void> setRecoveryKeys(
     clientProof: clientProof,
     totpCode: totpCode,
     recoveryCode: recoveryCode,
+    host: host,
   );
   // UPDATE "account_password" SET "recoveryKeysNonce" = $1,
   //   "recoveryKeysCipherText" = $2, "recoveryProofKey" = $3,
@@ -150,6 +154,7 @@ Future<AccountPassword> _proveOwner(
   required ByteData clientProof,
   String? totpCode,
   String? recoveryCode,
+  required String host,
 }) async {
   final proved = await provePassword(
     session,
@@ -157,6 +162,7 @@ Future<AccountPassword> _proveOwner(
     challenge: challenge,
     clientValue: clientValue,
     clientProof: clientProof,
+    host: host,
   );
   final row = proved.password;
   if (row.authUserId != person) {

packages/halkyon_base_server/lib/src/password/password_endpoint.dart

@@ -2,6 +2,7 @@ import 'dart:typed_data';
 
 import 'package:halkyon_base_server/src/auth/membership.dart';
 import 'package:halkyon_base_server/src/generated/protocol.dart';
+import 'package:halkyon_base_server/src/password/key_proof.dart';
 import 'package:halkyon_base_server/src/register/account_register.dart';
 import 'package:halkyon_base_server/src/register/people.dart';
 import 'package:serverpod/serverpod.dart';
@@ -60,6 +61,7 @@ class PasswordEndpoint extends Endpoint {
     String? totpCode,
     String? recoveryCode,
     required NewPassword password,
+    required String host,
   }) {
     final authenticated = session.authenticated!;
     return AccountRegister.of(session.serverpod).changePassword(
@@ -75,6 +77,7 @@ class PasswordEndpoint extends Endpoint {
       keepSession: Uuid.isValidUUID(fromString: authenticated.authId)
           ? UuidValue.fromString(authenticated.authId)
           : null,
+      host: deviceHostOn(session.serverpod, host),
     );
   }
 
@@ -92,6 +95,7 @@ class PasswordEndpoint extends Endpoint {
     String? recoveryCode,
     required WrappedKeys recoveryKeys,
     required ByteData recoveryProofKey,
+    required String host,
   }) => AccountRegister.of(session.serverpod).setRecoveryKeys(
     session,
     person: session.authenticated!.authUserId,
@@ -102,5 +106,6 @@ class PasswordEndpoint extends Endpoint {
     recoveryCode: recoveryCode,
     recoveryKeys: recoveryKeys,
     recoveryProofKey: recoveryProofKey,
+    host: deviceHostOn(session.serverpod, host),
   );
 }

packages/halkyon_base_server/lib/src/password/password_refusal.spy.yaml

@@ -46,3 +46,7 @@ values:
   ### code from one of those, which is missing or isn't right: a session
   ### alone adds no second factor.
   - wrongExistingCode
+  ### The device addressed this instance by another name than its own
+  ### (`apiServer.publicHost`): what it proves is bound to the name it
+  ### addressed, so the operator must configure the name devices use.
+  - otherInstance

packages/halkyon_base_server/lib/src/password/password_sign_in_endpoint.dart

@@ -2,6 +2,7 @@ import 'dart:typed_data';
 
 import 'package:halkyon_base_server/src/common/network.dart';
 import 'package:halkyon_base_server/src/generated/protocol.dart';
+import 'package:halkyon_base_server/src/password/key_proof.dart';
 import 'package:halkyon_base_server/src/password/passwords.dart';
 import 'package:halkyon_base_server/src/register/account_register.dart';
 import 'package:halkyon_base_server/src/register/people.dart';
@@ -41,6 +42,7 @@ class PasswordSignInEndpoint extends Endpoint {
     String? recoveryCode,
     UuidValue? request,
     String? code,
+    required String host,
   }) async {
     final proof = await AccountRegister.of(session.serverpod)
         .completePasswordSignIn(
@@ -52,6 +54,7 @@ class PasswordSignInEndpoint extends Endpoint {
           recoveryCode: recoveryCode,
           request: request,
           code: code,
+          host: deviceHostOn(session.serverpod, host),
         );
     final signedIn = await issueSession(
       session,

packages/halkyon_base_server/lib/src/password/passwords.dart

@@ -551,6 +551,7 @@ Future<PasswordProof> completePasswordSignIn(
   String? recoveryCode,
   UuidValue? request,
   String? code,
+  required String host,
 }) async {
   final keys = requirePasswordKeys(session.serverpod);
   final proved = await provePassword(
@@ -559,6 +560,7 @@ Future<PasswordProof> completePasswordSignIn(
     challenge: challenge,
     clientValue: clientValue,
     clientProof: clientProof,
+    host: host,
   );
   final account = proved.password.authUserId;
   final bool needsAuthenticator;
@@ -659,15 +661,18 @@ typedef PasswordProved = ({
 
 /// Takes [challenge] (once) and checks the device's proof against it, as
 /// [completePasswordSignIn] and the reset of a lost authenticator do; SRP's
-/// identity is the challenge's ID (16 bytes), so nobody learns an account's
-/// ID from its address. Refusals as [completePasswordSignIn]'s, but for the
-/// second factor.
+/// identity is [passwordIdentity] of the challenge's ID (so nobody learns an
+/// account's ID from its address) and of the [host] the device addressed
+/// (`deviceHost`, or the host a member names), so a proof a hostile
+/// instance relays here never counts. Refusals as
+/// [completePasswordSignIn]'s, but for the second factor.
 Future<PasswordProved> provePassword(
   Session session,
   PasswordKeys keys, {
   required UuidValue challenge,
   required ByteData clientValue,
   required ByteData clientProof,
+  required String host,
 }) async {
   final kept = await takeChallenge(
     session,
@@ -679,7 +684,7 @@ Future<PasswordProved> provePassword(
   final clientBytes = Uint8List.sublistView(clientValue);
   final verification = srpVerify(
     passwordGroup,
-    identity: challenge.toBytes(),
+    identity: passwordIdentity(challenge, host),
     salt: password == null ? decoy.salt : Uint8List.sublistView(password.salt),
     verifier: password == null
         ? decoy.verifier
@@ -972,7 +977,9 @@ Future<KeyProofChallenge> beginKeyProof(
 }
 
 /// Takes the key proof [challenge] (once) and checks [signature], the
-/// signature over [keyProofMessage] by the recovery phrase's own proof key
+/// signature over [keyProofMessage] (for the [host] the device addressed,
+/// the [purpose] and the [digest] of what it sets) by the recovery
+/// phrase's own proof key
 /// (`recoveryProofKey`: derived from the phrase alone, so the account's
 /// signing key, which every signed-in device keeps, proves nothing); the
 /// account's password row. Refused ([PasswordRefusedException]) for a
@@ -984,6 +991,9 @@ Future<AccountPassword> proveRecoveryPhrase(
   PasswordKeys keys, {
   required UuidValue challenge,
   required ByteData signature,
+  required String host,
+  required KeyProofPurpose purpose,
+  List<int> digest = const [],
 }) async {
   final kept = await takeChallenge(
     session,
@@ -996,7 +1006,13 @@ Future<AccountPassword> proveRecoveryPhrase(
   final password = await _passwordOf(session, kept.authUserId);
   final proofKey = password?.recoveryProofKey;
   final signed = await isAccountSignature(
-    keyProofMessage(challenge, _unhex(kept.secret)),
+    keyProofMessage(
+      challenge,
+      _unhex(kept.secret),
+      host: host,
+      purpose: purpose,
+      digest: digest,
+    ),
     signature: Uint8List.sublistView(signature),
     publicKey: proofKey == null
         ? decoy.recoveryProofKey

packages/halkyon_base_server/lib/src/register/account_register.dart

@@ -170,6 +170,7 @@ abstract interface class AccountRegister {
     String? recoveryCode,
     UuidValue? request,
     String? code,
+    required String host,
   });
 
   /// Signs up with the address [code] proves for [request] and the password
@@ -236,6 +237,7 @@ abstract interface class AccountRegister {
     String? code,
     UuidValue? keyChallenge,
     ByteData? signature,
+    required String host,
   });
 
   /// The first step of proving the recovery phrase for [address], the
@@ -256,6 +258,7 @@ abstract interface class AccountRegister {
     required NewPassword password,
     String? totpCode,
     String? recoveryCode,
+    required String host,
   });
 
   /// Asks for the reset of a whole account. Refusals as
@@ -298,6 +301,7 @@ abstract interface class AccountRegister {
     String? recoveryCode,
     required NewPassword password,
     UuidValue? keepSession,
+    required String host,
   });
 
   /// Replaces the wrapping of [person]'s keys under their recovery phrase
@@ -313,6 +317,7 @@ abstract interface class AccountRegister {
     String? recoveryCode,
     required WrappedKeys recoveryKeys,
     required ByteData recoveryProofKey,
+    required String host,
   });
 
   /// Deletes the account [person] with everything the register's server has

packages/halkyon_base_server/lib/src/register/instance_api.dart

@@ -236,6 +236,7 @@ Future<Map<String, Object?>?> _answer(
         recoveryCode: arguments.optionalString('recoveryCode'),
         request: arguments.optionalId('request'),
         code: arguments.optionalString('code'),
+        host: arguments.string('host'),
       );
       return {'proof': proof.toJson()};
     case RegisterOperation.signUpWithCode:
@@ -300,6 +301,7 @@ Future<Map<String, Object?>?> _answer(
         code: arguments.optionalString('code'),
         keyChallenge: arguments.optionalId('keyChallenge'),
         signature: arguments.optionalBytes('signature'),
+        host: arguments.string('host'),
       );
       return {'pending': pending.toJson()};
     case RegisterOperation.beginKeyProof:
@@ -317,6 +319,7 @@ Future<Map<String, Object?>?> _answer(
         password: arguments.model('password', NewPassword.fromJson),
         totpCode: arguments.optionalString('totpCode'),
         recoveryCode: arguments.optionalString('recoveryCode'),
+        host: arguments.string('host'),
       );
       return _sessionsEnded(ended);
     case RegisterOperation.startAccountReset:
@@ -354,6 +357,7 @@ Future<Map<String, Object?>?> _answer(
         recoveryCode: arguments.optionalString('recoveryCode'),
         password: arguments.model('password', NewPassword.fromJson),
         keepSession: arguments.optionalId('keepSession'),
+        host: arguments.string('host'),
       );
       return const {};
     case RegisterOperation.setRecoveryKeys:
@@ -367,6 +371,7 @@ Future<Map<String, Object?>?> _answer(
         recoveryCode: arguments.optionalString('recoveryCode'),
         recoveryKeys: arguments.model('recoveryKeys', WrappedKeys.fromJson),
         recoveryProofKey: arguments.bytes('recoveryProofKey'),
+        host: arguments.string('host'),
       );
       return const {};
   }

packages/halkyon_base_server/lib/src/register/local_register.dart

@@ -430,6 +430,7 @@ final class LocalRegister implements AccountRegister {
     String? recoveryCode,
     UuidValue? request,
     String? code,
+    required String host,
   }) => passwords.completePasswordSignIn(
     session,
     challenge: challenge,
@@ -439,6 +440,7 @@ final class LocalRegister implements AccountRegister {
     recoveryCode: recoveryCode,
     request: request,
     code: code,
+    host: host,
   );
 
   @override
@@ -520,6 +522,7 @@ final class LocalRegister implements AccountRegister {
     String? code,
     UuidValue? keyChallenge,
     ByteData? signature,
+    required String host,
   }) => recovery.resetAuthenticator(
     session,
     challenge: challenge,
@@ -531,6 +534,7 @@ final class LocalRegister implements AccountRegister {
     code: code,
     keyChallenge: keyChallenge,
     signature: signature,
+    host: host,
   );
 
   @override
@@ -548,6 +552,7 @@ final class LocalRegister implements AccountRegister {
     required NewPassword password,
     String? totpCode,
     String? recoveryCode,
+    required String host,
   }) => recovery.resetPasswordWithPhrase(
     session,
     challenge: challenge,
@@ -555,6 +560,7 @@ final class LocalRegister implements AccountRegister {
     password: password,
     totpCode: totpCode,
     recoveryCode: recoveryCode,
+    host: host,
   );
 
   @override
@@ -604,6 +610,7 @@ final class LocalRegister implements AccountRegister {
     String? recoveryCode,
     required NewPassword password,
     UuidValue? keepSession,
+    required String host,
   }) => change.changePassword(
     session,
     person: person,
@@ -614,6 +621,7 @@ final class LocalRegister implements AccountRegister {
     recoveryCode: recoveryCode,
     password: password,
     keepSession: keepSession,
+    host: host,
   );
 
   @override
@@ -627,6 +635,7 @@ final class LocalRegister implements AccountRegister {
     String? recoveryCode,
     required WrappedKeys recoveryKeys,
     required ByteData recoveryProofKey,
+    required String host,
   }) => change.setRecoveryKeys(
     session,
     person: person,
@@ -637,6 +646,7 @@ final class LocalRegister implements AccountRegister {
     recoveryCode: recoveryCode,
     recoveryKeys: recoveryKeys,
     recoveryProofKey: recoveryProofKey,
+    host: host,
   );
 
   @override

packages/halkyon_base_server/lib/src/register/remote_register.dart

@@ -321,9 +321,11 @@ final class RemoteRegister implements AccountRegister {
     String? recoveryCode,
     UuidValue? request,
     String? code,
+    required String host,
   }) async => _model<PasswordProof>(
     RegisterOperation.completePasswordSignIn,
     await _ask(RegisterOperation.completePasswordSignIn, {
+      'host': host,
       'challenge': challenge.uuid,
       'clientValue': _bytes(clientValue),
       'clientProof': _bytes(clientProof),
@@ -442,9 +444,11 @@ final class RemoteRegister implements AccountRegister {
     String? code,
     UuidValue? keyChallenge,
     ByteData? signature,
+    required String host,
   }) async => _model<ResetPending>(
     RegisterOperation.resetAuthenticator,
     await _ask(RegisterOperation.resetAuthenticator, {
+      'host': host,
       'challenge': challenge.uuid,
       'clientValue': _bytes(clientValue),
       'clientProof': _bytes(clientProof),
@@ -482,9 +486,11 @@ final class RemoteRegister implements AccountRegister {
     required NewPassword password,
     String? totpCode,
     String? recoveryCode,
+    required String host,
   }) async => _sessionsEnded(
     RegisterOperation.resetPasswordWithPhrase,
     await _ask(RegisterOperation.resetPasswordWithPhrase, {
+      'host': host,
       'challenge': challenge.uuid,
       'signature': _bytes(signature),
       'password': password.toJson(),
@@ -569,7 +575,9 @@ final class RemoteRegister implements AccountRegister {
     String? recoveryCode,
     required NewPassword password,
     UuidValue? keepSession,
+    required String host,
   }) => _ask(RegisterOperation.changePassword, {
+    'host': host,
     'person': person.uuid,
     'challenge': challenge.uuid,
     'clientValue': _bytes(clientValue),
@@ -591,7 +599,9 @@ final class RemoteRegister implements AccountRegister {
     String? recoveryCode,
     required WrappedKeys recoveryKeys,
     required ByteData recoveryProofKey,
+    required String host,
   }) => _ask(RegisterOperation.setRecoveryKeys, {
+    'host': host,
     'person': person.uuid,
     'challenge': challenge.uuid,
     'clientValue': _bytes(clientValue),