fix(cat-voices): update key derivation path (#1301)

* fix(cat-voices): update key derivation path

* docs: add source

* chore: code cleanup

* docs: move relevant docs

* chore: extract account constant

Co-authored-by: Steven Johnson <[email protected]>

* chore: reformat

---------

Co-authored-by: Steven Johnson <[email protected]>

Author: dtscalac

catalyst_voices/packages/internal/catalyst_voices_models/lib/src/user/account_role.dart

@@ -1,18 +1,18 @@
 enum AccountRole {
-  voter(roleNumber: 0),
+  /// An account role that is assigned to every account.
+  /// Allows to vote for proposals.
+  voter(number: 0),
 
-  // TODO(dtscalac): the RBAC specification doesn't define yet the role number
-  // for the proposer, replace this arbitrary number when it's specified.
-  proposer(roleNumber: 1),
+  /// A delegated representative that can vote on behalf of other accounts.
+  drep(number: 1),
 
-  // TODO(dtscalac): the RBAC specification doesn't define yet the role number
-  // for the drep, replace this arbitrary number when it's specified.
-  drep(roleNumber: 2);
+  /// An account role that can create new proposals.
+  proposer(number: 3);
 
   /// The RBAC specified role number.
-  final int roleNumber;
+  final int number;
 
-  const AccountRole({required this.roleNumber});
+  const AccountRole({required this.number});
 
   /// Returns the role which is assigned to every user.
   static AccountRole get root => voter;

catalyst_voices/packages/internal/catalyst_voices_services/lib/src/crypto/key_derivation.dart

@@ -3,6 +3,10 @@ import 'package:catalyst_voices_models/catalyst_voices_models.dart';
 
 /// Derives key pairs from a seed phrase.
 final class KeyDerivation {
+  /// See: https://github.com/input-output-hk/catalyst-voices/pull/1300
+  static const int _purpose = 508;
+  static const int _type = 139;
+  static const int _account = 0; // Future Use
   final CatalystKeyDerivation _keyDerivation;
 
   const KeyDerivation(this._keyDerivation);
@@ -44,9 +48,7 @@ final class KeyDerivation {
 
   /// The path feed into key derivation algorithm
   /// to generate a key pair from a seed phrase.
-  ///
-  // TODO(dtscalac): update when RBAC specifies it
   String _roleKeyDerivationPath(AccountRole role) {
-    return "m/${role.roleNumber}'/1234'";
+    return "m/$_purpose'/$_type'/$_account'/${role.number}/0";
   }
 }

catalyst_voices/packages/internal/catalyst_voices_services/lib/src/registration/registration_transaction_builder.dart

@@ -82,7 +82,7 @@ final class RegistrationTransactionBuilder {
           // TODO(dtscalac): when RBAC specification will define other roles
           // they should be registered here
           RoleData(
-            roleNumber: AccountRole.root.roleNumber,
+            roleNumber: AccountRole.root.number,
             roleSigningKey: const LocalKeyReference(
               keyType: LocalKeyReferenceType.x509Certs,
               offset: 0,

catalyst_voices/packages/internal/catalyst_voices_services/test/src/crypto/key_derivation_test.dart

@@ -31,7 +31,7 @@ void main() {
       for (final role in AccountRole.values) {
         final keyPair = await keyDerivation.deriveKeyPair(
           masterKey: masterKey,
-          path: "m/${role.roleNumber}'/1234'",
+          path: "m/${role.number}'/1234'",
         );
         expect(keyPair, isNotNull);
       }