diff --git a/catalyst_voices/apps/voices/lib/pages/proposal_builder/proposal_builder_page.dart b/catalyst_voices/apps/voices/lib/pages/proposal_builder/proposal_builder_page.dart
index 39860ed675f1..f928c78847a8 100644
--- a/catalyst_voices/apps/voices/lib/pages/proposal_builder/proposal_builder_page.dart
+++ b/catalyst_voices/apps/voices/lib/pages/proposal_builder/proposal_builder_page.dart
@@ -15,10 +15,9 @@ import 'package:catalyst_voices/pages/workspace/submission_closing_warning_dialo
 import 'package:catalyst_voices/routes/routes.dart';
 import 'package:catalyst_voices/routes/routing/proposal_builder_route.dart';
 import 'package:catalyst_voices/widgets/modals/comment/submit_comment_error_dialog.dart';
+import 'package:catalyst_voices/widgets/modals/proposals/proposal_error_dialog.dart';
 import 'package:catalyst_voices/widgets/modals/proposals/proposal_limit_reached_dialog.dart';
-import 'package:catalyst_voices/widgets/modals/proposals/publish_proposal_error_dialog.dart';
 import 'package:catalyst_voices/widgets/modals/proposals/publish_proposal_iteration_dialog.dart';
-import 'package:catalyst_voices/widgets/modals/proposals/submit_proposal_error_dialog.dart';
 import 'package:catalyst_voices/widgets/modals/proposals/submit_proposal_for_review_dialog.dart';
 import 'package:catalyst_voices/widgets/modals/proposals/unlock_edit_proposal.dart';
 import 'package:catalyst_voices/widgets/snackbar/common_snackbars.dart';
@@ -142,8 +141,14 @@ class _ProposalBuilderBodyState extends State<_ProposalBuilderBody>
         unawaited(_showPublishException(error));
       case ProposalBuilderSubmitException():
         unawaited(_showSubmitException(error));
+      case ProposalBuilderLimitReachedException():
+        unawaited(_showLimitReachedException(error));
+      case ProposalBuilderDocumentSignException():
+        unawaited(_showDocumentSignException(error));
       case LocalizedUnknownPublishCommentException():
         unawaited(_showCommentException(error));
+      case LocalizedException():
+        unawaited(_showGenericException(error));
       default:
         super.handleError(error);
     }
@@ -277,6 +282,14 @@ class _ProposalBuilderBodyState extends State<_ProposalBuilderBody>
     );
   }
 
+  Future<void> _showDocumentSignException(ProposalBuilderDocumentSignException error) {
+    return ProposalErrorDialog.show(
+      context: context,
+      title: error.title(context),
+      message: error.message(context),
+    );
+  }
+
   Future<void> _showEmailNotVerifiedDialog() async {
     final openAccount = await EmailNotVerifiedDialog.show(context);
 
@@ -317,6 +330,22 @@ class _ProposalBuilderBodyState extends State<_ProposalBuilderBody>
     });
   }
 
+  Future<void> _showGenericException(LocalizedException error) {
+    return ProposalErrorDialog.show(
+      context: context,
+      title: context.l10n.somethingWentWrong,
+      message: error.message(context),
+    );
+  }
+
+  Future<void> _showLimitReachedException(ProposalBuilderLimitReachedException error) {
+    return ProposalErrorDialog.show(
+      context: context,
+      title: error.title(context),
+      message: error.message(context),
+    );
+  }
+
   Future<void> _showProposalLimitReachedDialog(
     MaxProposalsLimitReachedSignal signal,
   ) {
@@ -344,9 +373,10 @@ class _ProposalBuilderBodyState extends State<_ProposalBuilderBody>
   }
 
   Future<void> _showPublishException(ProposalBuilderPublishException error) {
-    return PublishProposalErrorDialog.show(
+    return ProposalErrorDialog.show(
       context: context,
-      exception: error,
+      title: error.title(context),
+      message: error.message(context),
     );
   }
 
@@ -380,9 +410,10 @@ class _ProposalBuilderBodyState extends State<_ProposalBuilderBody>
   }
 
   Future<void> _showSubmitException(ProposalBuilderSubmitException error) {
-    return SubmitProposalErrorDialog.show(
+    return ProposalErrorDialog.show(
       context: context,
-      exception: error,
+      title: error.title(context),
+      message: error.message(context),
     );
   }
 
diff --git a/catalyst_voices/apps/voices/lib/widgets/modals/proposals/submit_proposal_error_dialog.dart b/catalyst_voices/apps/voices/lib/widgets/modals/proposals/proposal_error_dialog.dart
similarity index 73%
rename from catalyst_voices/apps/voices/lib/widgets/modals/proposals/submit_proposal_error_dialog.dart
rename to catalyst_voices/apps/voices/lib/widgets/modals/proposals/proposal_error_dialog.dart
index 742951b75ee3..6c782b09db77 100644
--- a/catalyst_voices/apps/voices/lib/widgets/modals/proposals/submit_proposal_error_dialog.dart
+++ b/catalyst_voices/apps/voices/lib/widgets/modals/proposals/proposal_error_dialog.dart
@@ -4,27 +4,27 @@ import 'package:catalyst_voices/widgets/modals/voices_info_dialog.dart';
 import 'package:catalyst_voices_assets/catalyst_voices_assets.dart';
 import 'package:catalyst_voices_brands/catalyst_voices_brands.dart';
 import 'package:catalyst_voices_localization/catalyst_voices_localization.dart';
-import 'package:catalyst_voices_view_models/catalyst_voices_view_models.dart';
 import 'package:flutter/material.dart';
 
-/// Error dialog when submitting proposal for review fails.
-class SubmitProposalErrorDialog {
+/// Generic error dialog related to proposal errors.
+class ProposalErrorDialog {
   static Future<void> show({
     required BuildContext context,
-    required ProposalBuilderSubmitException exception,
+    required String title,
+    required String message,
   }) {
     return VoicesDialog.show(
       context: context,
       routeSettings: const RouteSettings(
-        name: '/proposal-builder/submit-error',
+        name: '/proposal-builder/error',
       ),
       builder: (context) {
         return VoicesInfoDialog(
           icon: VoicesAssets.icons.exclamation.buildIcon(
             color: Theme.of(context).colors.iconsWarning,
           ),
-          title: Text(exception.title(context)),
-          message: Text(exception.message(context)),
+          title: Text(title),
+          message: Text(message),
           action: VoicesFilledButton(
             onTap: () => Navigator.of(context).pop(),
             child: Text(context.l10n.okay),
diff --git a/catalyst_voices/apps/voices/lib/widgets/modals/proposals/publish_proposal_error_dialog.dart b/catalyst_voices/apps/voices/lib/widgets/modals/proposals/publish_proposal_error_dialog.dart
deleted file mode 100644
index 58d58a957f4c..000000000000
--- a/catalyst_voices/apps/voices/lib/widgets/modals/proposals/publish_proposal_error_dialog.dart
+++ /dev/null
@@ -1,36 +0,0 @@
-import 'package:catalyst_voices/widgets/buttons/voices_filled_button.dart';
-import 'package:catalyst_voices/widgets/modals/voices_dialog.dart';
-import 'package:catalyst_voices/widgets/modals/voices_info_dialog.dart';
-import 'package:catalyst_voices_assets/catalyst_voices_assets.dart';
-import 'package:catalyst_voices_brands/catalyst_voices_brands.dart';
-import 'package:catalyst_voices_localization/catalyst_voices_localization.dart';
-import 'package:catalyst_voices_view_models/catalyst_voices_view_models.dart';
-import 'package:flutter/material.dart';
-
-/// Error dialog when publishing proposal to server fails.
-class PublishProposalErrorDialog {
-  static Future<void> show({
-    required BuildContext context,
-    required ProposalBuilderPublishException exception,
-  }) {
-    return VoicesDialog.show(
-      context: context,
-      routeSettings: const RouteSettings(
-        name: '/proposal-builder/publish-error',
-      ),
-      builder: (context) {
-        return VoicesInfoDialog(
-          icon: VoicesAssets.icons.exclamation.buildIcon(
-            color: Theme.of(context).colors.iconsWarning,
-          ),
-          title: Text(exception.title(context)),
-          message: Text(exception.message(context)),
-          action: VoicesFilledButton(
-            onTap: () => Navigator.of(context).pop(),
-            child: Text(context.l10n.okay),
-          ),
-        );
-      },
-    );
-  }
-}
diff --git a/catalyst_voices/packages/internal/catalyst_voices_blocs/lib/src/proposal_builder/proposal_builder_bloc.dart b/catalyst_voices/packages/internal/catalyst_voices_blocs/lib/src/proposal_builder/proposal_builder_bloc.dart
index 57bfba8e6689..81a557ff9839 100644
--- a/catalyst_voices/packages/internal/catalyst_voices_blocs/lib/src/proposal_builder/proposal_builder_bloc.dart
+++ b/catalyst_voices/packages/internal/catalyst_voices_blocs/lib/src/proposal_builder/proposal_builder_bloc.dart
@@ -790,9 +790,21 @@ final class ProposalBuilderBloc extends Bloc<ProposalBuilderEvent, ProposalBuild
         versions: updatedVersions,
       );
       emitSignal(const PublishedProposalBuilderSignal());
+    } on ProposalLimitReachedException {
+      _logger.info('publishProposal: limit reached');
+      emitError(const ProposalBuilderLimitReachedException());
+    } on DocumentSignException catch (error, stackTrace) {
+      _logger.severe('publishProposal: failed to sign the document', error, stackTrace);
+      emitError(const ProposalBuilderDocumentSignException());
     } catch (error, stackTrace) {
-      _logger.severe('PublishProposal', error, stackTrace);
-      emitError(const ProposalBuilderPublishException());
+      _logger.severe('publishProposal', error, stackTrace);
+
+      emitError(
+        LocalizedException.create(
+          error,
+          fallback: () => const ProposalBuilderPublishException(),
+        ),
+      );
     } finally {
       emit(state.copyWith(isChanging: false));
     }
@@ -1092,9 +1104,21 @@ final class ProposalBuilderBloc extends Bloc<ProposalBuilderEvent, ProposalBuild
           // already submitted, do nothing
           break;
       }
+    } on ProposalLimitReachedException {
+      _logger.info('SubmitProposalForReview: limit reached');
+      emitError(const ProposalBuilderLimitReachedException());
+    } on DocumentSignException catch (error, stackTrace) {
+      _logger.severe('publishProposal: failed to sign the document', error, stackTrace);
+      emitError(const ProposalBuilderDocumentSignException());
     } catch (error, stackTrace) {
       _logger.severe('SubmitProposalForReview', error, stackTrace);
-      emitError(const ProposalBuilderSubmitException());
+
+      emitError(
+        LocalizedException.create(
+          error,
+          fallback: () => const ProposalBuilderSubmitException(),
+        ),
+      );
     } finally {
       emit(state.copyWith(isChanging: false));
     }
diff --git a/catalyst_voices/packages/internal/catalyst_voices_localization/lib/l10n/intl_en.arb b/catalyst_voices/packages/internal/catalyst_voices_localization/lib/l10n/intl_en.arb
index 02e241169ee1..a0b09726041e 100644
--- a/catalyst_voices/packages/internal/catalyst_voices_localization/lib/l10n/intl_en.arb
+++ b/catalyst_voices/packages/internal/catalyst_voices_localization/lib/l10n/intl_en.arb
@@ -2194,6 +2194,22 @@
   "@proposalEditorDeleteDialogTitle": {
     "description": "A title for the dialog to confirm proposal deletion."
   },
+  "proposalEditorDocumentSignErrorMessage": "We couldn't sign the proposal, please try again later.",
+  "@proposalEditorDocumentSignErrorMessage": {
+    "description": "Dialog message in proposal editor when user couldn't sign the proposal."
+  },
+  "proposalEditorDocumentSignErrorTitle": "Unable to Sign the Proposal",
+  "@proposalEditorDocumentSignErrorTitle": {
+    "description": "Dialog title in proposal editor when user couldn't sign the proposal."
+  },
+  "proposalEditorLimitReachedErrorMessage": "You have reached the maximum number of proposals allowed.",
+  "@proposalEditorLimitReachedErrorMessage": {
+    "description": "Dialog message in proposal editor when user has reached the max proposals limit."
+  },
+  "proposalEditorLimitReachedErrorTitle": "Unable to Publish Proposal",
+  "@proposalEditorLimitReachedErrorTitle": {
+    "description": "Dialog title in proposal editor when user has reached the max proposals limit."
+  },
   "proposalEditorNotAnswered": "Not Answered",
   "@proposalEditorNotAnswered": {
     "description": "Placeholder text when a property has been not filled."
diff --git a/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/catalyst_voices_models.dart b/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/catalyst_voices_models.dart
index 098533ef6c57..b7f6c05258b0 100644
--- a/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/catalyst_voices_models.dart
+++ b/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/catalyst_voices_models.dart
@@ -51,6 +51,7 @@ export 'document/enums/document_content_media_type.dart';
 export 'document/enums/document_property_format.dart';
 export 'document/enums/document_property_type.dart';
 export 'document/exception/document_import_invalid_data_exception.dart';
+export 'document/exception/document_sign_exception.dart';
 export 'document/schema/document_schema.dart';
 export 'document/schema/property/document_property_schema.dart';
 export 'document/specialized/comment_document.dart';
diff --git a/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/document/exception/document_sign_exception.dart b/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/document/exception/document_sign_exception.dart
new file mode 100644
index 000000000000..695913337851
--- /dev/null
+++ b/catalyst_voices/packages/internal/catalyst_voices_models/lib/src/document/exception/document_sign_exception.dart
@@ -0,0 +1,11 @@
+import 'package:equatable/equatable.dart';
+
+/// An exception denoting a problem with signed document creation.
+class DocumentSignException extends Equatable implements Exception {
+  final String message;
+
+  const DocumentSignException(this.message);
+
+  @override
+  List<Object?> get props => [message];
+}
diff --git a/catalyst_voices/packages/internal/catalyst_voices_repositories/lib/src/signed_document/signed_document_manager_impl.dart b/catalyst_voices/packages/internal/catalyst_voices_repositories/lib/src/signed_document/signed_document_manager_impl.dart
index 36c0b0ca2af0..23004a97bbaa 100644
--- a/catalyst_voices/packages/internal/catalyst_voices_repositories/lib/src/signed_document/signed_document_manager_impl.dart
+++ b/catalyst_voices/packages/internal/catalyst_voices_repositories/lib/src/signed_document/signed_document_manager_impl.dart
@@ -48,21 +48,25 @@ final class SignedDocumentManagerImpl implements SignedDocumentManager {
     required CatalystId catalystId,
     required CatalystPrivateKey privateKey,
   }) async {
-    final compressedPayload = await _brotliCompressPayload(document.toBytes());
-
-    final coseSign = await CoseSign.sign(
-      protectedHeaders: metadata.asCoseProtectedHeaders,
-      unprotectedHeaders: metadata.asCoseUnprotectedHeaders,
-      payload: compressedPayload,
-      signers: [_CatalystSigner(catalystId, privateKey)],
-    );
-
-    return _CoseSignedDocument(
-      coseSign: coseSign,
-      payload: document,
-      metadata: metadata,
-      signers: [catalystId],
-    );
+    try {
+      final compressedPayload = await _brotliCompressPayload(document.toBytes());
+
+      final coseSign = await CoseSign.sign(
+        protectedHeaders: metadata.asCoseProtectedHeaders,
+        unprotectedHeaders: metadata.asCoseUnprotectedHeaders,
+        payload: compressedPayload,
+        signers: [_CatalystSigner(catalystId, privateKey)],
+      );
+
+      return _CoseSignedDocument(
+        coseSign: coseSign,
+        payload: document,
+        metadata: metadata,
+        signers: [catalystId],
+      );
+    } on CoseSignException catch (error) {
+      throw DocumentSignException('Failed to create a signed document!\nSource: ${error.source}');
+    }
   }
 
   Future<Uint8List> _brotliCompressPayload(Uint8List payload) async {
diff --git a/catalyst_voices/packages/internal/catalyst_voices_view_models/lib/src/proposal_builder/exception/proposal_builder_exception.dart b/catalyst_voices/packages/internal/catalyst_voices_view_models/lib/src/proposal_builder/exception/proposal_builder_exception.dart
index 8f278915de33..1347b1df2fed 100644
--- a/catalyst_voices/packages/internal/catalyst_voices_view_models/lib/src/proposal_builder/exception/proposal_builder_exception.dart
+++ b/catalyst_voices/packages/internal/catalyst_voices_view_models/lib/src/proposal_builder/exception/proposal_builder_exception.dart
@@ -2,6 +2,35 @@ import 'package:catalyst_voices_localization/catalyst_voices_localization.dart';
 import 'package:catalyst_voices_view_models/src/exception/localized_exception.dart';
 import 'package:flutter/material.dart';
 
+/// An exception thrown when the app cannot sign the document on the user's behalf.
+final class ProposalBuilderDocumentSignException extends LocalizedException {
+  const ProposalBuilderDocumentSignException();
+
+  @override
+  String message(BuildContext context) {
+    return context.l10n.proposalEditorDocumentSignErrorMessage;
+  }
+
+  String title(BuildContext context) {
+    return context.l10n.proposalEditorDocumentSignErrorTitle;
+  }
+}
+
+/// An exception thrown attempting to create / import a new
+/// proposal when the user has reached the limit.
+final class ProposalBuilderLimitReachedException extends LocalizedException {
+  const ProposalBuilderLimitReachedException();
+
+  @override
+  String message(BuildContext context) {
+    return context.l10n.proposalEditorLimitReachedErrorMessage;
+  }
+
+  String title(BuildContext context) {
+    return context.l10n.proposalEditorLimitReachedErrorTitle;
+  }
+}
+
 /// Localized exception thrown when a proposal builder fails to publish a proposal.
 final class ProposalBuilderPublishException extends LocalizedException {
   const ProposalBuilderPublishException();
diff --git a/catalyst_voices/packages/libs/catalyst_cose/lib/catalyst_cose.dart b/catalyst_voices/packages/libs/catalyst_cose/lib/catalyst_cose.dart
index 5b124e4669eb..eb1772eb084e 100644
--- a/catalyst_voices/packages/libs/catalyst_cose/lib/catalyst_cose.dart
+++ b/catalyst_voices/packages/libs/catalyst_cose/lib/catalyst_cose.dart
@@ -1,6 +1,7 @@
 export 'src/cose_constants.dart';
 export 'src/cose_sign.dart';
 export 'src/cose_sign1.dart';
+export 'src/exception/cose_exception.dart';
 export 'src/types/cose_headers.dart';
 export 'src/types/string_or_int.dart';
 export 'src/types/uuid.dart';
diff --git a/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign.dart b/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign.dart
index 108e7b660c04..a5e7e9d79da3 100644
--- a/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign.dart
+++ b/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign.dart
@@ -1,6 +1,7 @@
 import 'dart:typed_data';
 
 import 'package:catalyst_cose/src/cose_constants.dart';
+import 'package:catalyst_cose/src/exception/cose_exception.dart';
 import 'package:catalyst_cose/src/types/cose_headers.dart';
 import 'package:cbor/cbor.dart';
 import 'package:collection/collection.dart';
@@ -133,40 +134,47 @@ final class CoseSign extends Equatable {
     required Uint8List payload,
     required List<CatalystCoseSigner> signers,
   }) async {
-    // TODO(dt-iohk): remove when server stops
-    // requiring alg header in body protected headers.
-    protectedHeaders = protectedHeaders.copyWith(
-      alg: () => signers.firstOrNull?.alg,
-    );
-
-    final signatures = <CoseSignature>[];
-    for (final signer in signers) {
-      final signatureProtectedHeaders = CoseHeaders.protected(
-        alg: signer.alg,
-        kid: await signer.kid,
+    try {
+      // TODO(dt-iohk): remove when server stops
+      // requiring alg header in body protected headers.
+      protectedHeaders = protectedHeaders.copyWith(
+        alg: () => signers.firstOrNull?.alg,
       );
 
-      final toBeSigned = _createCoseSignSigStructureBytes(
-        bodyProtectedHeaders: protectedHeaders,
-        signatureProtectedHeaders: signatureProtectedHeaders,
+      final signatures = <CoseSignature>[];
+      for (final signer in signers) {
+        final signatureProtectedHeaders = CoseHeaders.protected(
+          alg: signer.alg,
+          kid: await signer.kid,
+        );
+
+        final toBeSigned = _createCoseSignSigStructureBytes(
+          bodyProtectedHeaders: protectedHeaders,
+          signatureProtectedHeaders: signatureProtectedHeaders,
+          payload: payload,
+        );
+
+        final signature = CoseSignature(
+          protectedHeaders: signatureProtectedHeaders,
+          unprotectedHeaders: const CoseHeaders.unprotected(),
+          signature: await signer.sign(toBeSigned),
+        );
+
+        signatures.add(signature);
+      }
+
+      return CoseSign(
+        protectedHeaders: protectedHeaders,
+        unprotectedHeaders: unprotectedHeaders,
         payload: payload,
+        signatures: signatures,
       );
-
-      final signature = CoseSignature(
-        protectedHeaders: signatureProtectedHeaders,
-        unprotectedHeaders: const CoseHeaders.unprotected(),
-        signature: await signer.sign(toBeSigned),
+    } catch (error) {
+      throw CoseSignException(
+        message: 'Failed to create a CoseSign instance',
+        source: error,
       );
-
-      signatures.add(signature);
     }
-
-    return CoseSign(
-      protectedHeaders: protectedHeaders,
-      unprotectedHeaders: unprotectedHeaders,
-      payload: payload,
-      signatures: signatures,
-    );
   }
 
   static CborList _createCoseSignSigStructure({
diff --git a/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign1.dart b/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign1.dart
index 29de1d158198..2484e650b613 100644
--- a/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign1.dart
+++ b/catalyst_voices/packages/libs/catalyst_cose/lib/src/cose_sign1.dart
@@ -1,6 +1,7 @@
 import 'dart:typed_data';
 
 import 'package:catalyst_cose/src/cose_constants.dart';
+import 'package:catalyst_cose/src/exception/cose_exception.dart';
 import 'package:catalyst_cose/src/types/cose_headers.dart';
 import 'package:cbor/cbor.dart';
 import 'package:equatable/equatable.dart';
@@ -114,32 +115,39 @@ final class CoseSign1 extends Equatable {
     required Uint8List payload,
     required CatalystCoseSigner signer,
   }) async {
-    final kid = await signer.kid;
+    try {
+      final kid = await signer.kid;
 
-    protectedHeaders = protectedHeaders.copyWith(
-      alg: () => signer.alg,
-      kid: () => kid,
-    );
+      protectedHeaders = protectedHeaders.copyWith(
+        alg: () => signer.alg,
+        kid: () => kid,
+      );
 
-    final sigStructure = _createCoseSign1SigStructure(
-      protectedHeader: protectedHeaders.toCbor(),
-      payload: CborBytes(payload),
-    );
+      final sigStructure = _createCoseSign1SigStructure(
+        protectedHeader: protectedHeaders.toCbor(),
+        payload: CborBytes(payload),
+      );
 
-    final toBeSigned = Uint8List.fromList(
-      cbor.encode(
-        CborBytes(
-          cbor.encode(sigStructure),
+      final toBeSigned = Uint8List.fromList(
+        cbor.encode(
+          CborBytes(
+            cbor.encode(sigStructure),
+          ),
         ),
-      ),
-    );
+      );
 
-    return CoseSign1(
-      protectedHeaders: protectedHeaders,
-      unprotectedHeaders: unprotectedHeaders,
-      payload: payload,
-      signature: await signer.sign(toBeSigned),
-    );
+      return CoseSign1(
+        protectedHeaders: protectedHeaders,
+        unprotectedHeaders: unprotectedHeaders,
+        payload: payload,
+        signature: await signer.sign(toBeSigned),
+      );
+    } catch (error) {
+      throw CoseSignException(
+        message: 'Failed to create a CoseSign1 instance',
+        source: error,
+      );
+    }
   }
 
   static CborValue _createCoseSign1SigStructure({
diff --git a/catalyst_voices/packages/libs/catalyst_cose/lib/src/exception/cose_exception.dart b/catalyst_voices/packages/libs/catalyst_cose/lib/src/exception/cose_exception.dart
new file mode 100644
index 000000000000..91c76727b277
--- /dev/null
+++ b/catalyst_voices/packages/libs/catalyst_cose/lib/src/exception/cose_exception.dart
@@ -0,0 +1,19 @@
+import 'package:equatable/equatable.dart';
+
+/// A generalized COSE sign exception.
+final class CoseSignException extends Equatable implements Exception {
+  /// A message describing the exception.
+  final String message;
+
+  /// The source of the exception, if any.
+  final Object? source;
+
+  /// The default constructor for the [CoseSignException].
+  const CoseSignException({
+    required this.message,
+    this.source,
+  });
+
+  @override
+  List<Object?> get props => [message, source];
+}