diff --git a/pkg/api/message/publish_test.go b/pkg/api/message/publish_test.go
index 740dcbed..3e8cc309 100644
--- a/pkg/api/message/publish_test.go
+++ b/pkg/api/message/publish_test.go
@@ -22,7 +22,10 @@ func TestPublishEnvelope(t *testing.T) {
 	api, db, _, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
 
-	payerEnvelope := envelopeTestUtils.CreatePayerEnvelope(t)
+	payerEnvelope := envelopeTestUtils.CreatePayerEnvelope(
+		t,
+		envelopeTestUtils.DefaultClientEnvelopeNodeId,
+	)
 
 	resp, err := api.PublishPayerEnvelopes(
 		context.Background(),
@@ -70,7 +73,10 @@ func TestUnmarshalErrorOnPublish(t *testing.T) {
 	api, _, _, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
 
-	envelope := envelopeTestUtils.CreatePayerEnvelope(t)
+	envelope := envelopeTestUtils.CreatePayerEnvelope(
+		t,
+		envelopeTestUtils.DefaultClientEnvelopeNodeId,
+	)
 	envelope.UnsignedClientEnvelope = []byte("invalidbytes")
 	_, err := api.PublishPayerEnvelopes(
 		context.Background(),
@@ -81,19 +87,42 @@ func TestUnmarshalErrorOnPublish(t *testing.T) {
 	require.ErrorContains(t, err, "invalid wire-format data")
 }
 
-func TestMismatchingOriginatorOnPublish(t *testing.T) {
+func TestMismatchingAADOriginatorOnPublishNoLongerFails(t *testing.T) {
 	api, _, _, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
 
+	nid := envelopeTestUtils.DefaultClientEnvelopeNodeId + 100
+
 	clientEnv := envelopeTestUtils.CreateClientEnvelope()
-	nodeId := uint32(2)
 	// nolint:staticcheck
-	clientEnv.Aad.TargetOriginator = &nodeId
+	clientEnv.Aad.TargetOriginator = &nid
+	_, err := api.PublishPayerEnvelopes(
+		context.Background(),
+		&message_api.PublishPayerEnvelopesRequest{
+			PayerEnvelopes: []*envelopes.PayerEnvelope{
+				envelopeTestUtils.CreatePayerEnvelope(
+					t,
+					envelopeTestUtils.DefaultClientEnvelopeNodeId,
+					clientEnv,
+				),
+			},
+		},
+	)
+	require.NoError(t, err)
+}
+
+func TestMismatchingOriginatorOnPublish(t *testing.T) {
+	api, _, _, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
+	defer cleanup()
+
+	nid := envelopeTestUtils.DefaultClientEnvelopeNodeId + 100
+
+	clientEnv := envelopeTestUtils.CreateClientEnvelope()
 	_, err := api.PublishPayerEnvelopes(
 		context.Background(),
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{
-				envelopeTestUtils.CreatePayerEnvelope(t, clientEnv),
+				envelopeTestUtils.CreatePayerEnvelope(t, nid, clientEnv),
 			},
 		},
 	)
@@ -110,7 +139,11 @@ func TestMissingTopicOnPublish(t *testing.T) {
 		context.Background(),
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{
-				envelopeTestUtils.CreatePayerEnvelope(t, clientEnv),
+				envelopeTestUtils.CreatePayerEnvelope(
+					t,
+					envelopeTestUtils.DefaultClientEnvelopeNodeId,
+					clientEnv,
+				),
 			},
 		},
 	)
@@ -120,11 +153,12 @@ func TestMissingTopicOnPublish(t *testing.T) {
 func TestKeyPackageValidationSuccess(t *testing.T) {
 	api, _, apiMocks, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
-	nodeId := uint32(100)
+
+	nid := envelopeTestUtils.DefaultClientEnvelopeNodeId
 
 	clientEnv := envelopeTestUtils.CreateClientEnvelope(&envelopes.AuthenticatedData{
 		TargetTopic:      topic.NewTopic(topic.TOPIC_KIND_KEY_PACKAGES_V1, []byte{1, 2, 3}).Bytes(),
-		TargetOriginator: &nodeId,
+		TargetOriginator: &nid,
 		DependsOn:        &envelopes.Cursor{},
 	})
 	clientEnv.Payload = &envelopes.ClientEnvelope_UploadKeyPackage{
@@ -150,7 +184,11 @@ func TestKeyPackageValidationSuccess(t *testing.T) {
 		context.Background(),
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{
-				envelopeTestUtils.CreatePayerEnvelope(t, clientEnv),
+				envelopeTestUtils.CreatePayerEnvelope(
+					t,
+					envelopeTestUtils.DefaultClientEnvelopeNodeId,
+					clientEnv,
+				),
 			},
 		},
 	)
@@ -160,11 +198,12 @@ func TestKeyPackageValidationSuccess(t *testing.T) {
 func TestKeyPackageValidationFail(t *testing.T) {
 	api, _, apiMocks, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
-	nodeId := uint32(100)
+
+	nid := envelopeTestUtils.DefaultClientEnvelopeNodeId
 
 	clientEnv := envelopeTestUtils.CreateClientEnvelope(&envelopes.AuthenticatedData{
 		TargetTopic:      topic.NewTopic(topic.TOPIC_KIND_KEY_PACKAGES_V1, []byte{1, 2, 3}).Bytes(),
-		TargetOriginator: &nodeId,
+		TargetOriginator: &nid,
 		DependsOn:        &envelopes.Cursor{},
 	})
 	clientEnv.Payload = &envelopes.ClientEnvelope_UploadKeyPackage{
@@ -190,7 +229,7 @@ func TestKeyPackageValidationFail(t *testing.T) {
 		context.Background(),
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{
-				envelopeTestUtils.CreatePayerEnvelope(t, clientEnv),
+				envelopeTestUtils.CreatePayerEnvelope(t, nid, clientEnv),
 			},
 		},
 	)
@@ -201,11 +240,16 @@ func TestPublishEnvelopeBlockchainCursorAhead(t *testing.T) {
 	api, _, _, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
 
-	err := publishPayerEnvelopeWithNodeIDAndCursor(t, api, 100, &envelopes.Cursor{
-		NodeIdToSequenceId: map[uint32]uint64{
-			1: 105,
+	err := publishPayerEnvelopeWithNodeIDAndCursor(
+		t,
+		api,
+		envelopeTestUtils.DefaultClientEnvelopeNodeId,
+		&envelopes.Cursor{
+			NodeIdToSequenceId: map[uint32]uint64{
+				1: 105,
+			},
 		},
-	})
+	)
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "DependsOn has not been seen by this node")
 }
@@ -220,7 +264,7 @@ func publishPayerEnvelopeWithNodeIDAndCursor(
 		context.Background(),
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{envelopeTestUtils.CreatePayerEnvelope(
-				t,
+				t, nodeId,
 				envelopeTestUtils.CreateClientEnvelope(&envelopes.AuthenticatedData{
 					TargetOriginator: &nodeId,
 					TargetTopic:      targetTopic,
@@ -237,11 +281,16 @@ func TestPublishEnvelopeOriginatorUnknown(t *testing.T) {
 	api, _, _, cleanup := apiTestUtils.NewTestReplicationAPIClient(t)
 	defer cleanup()
 
-	err := publishPayerEnvelopeWithNodeIDAndCursor(t, api, 100, &envelopes.Cursor{
-		NodeIdToSequenceId: map[uint32]uint64{
-			1600: 1,
+	err := publishPayerEnvelopeWithNodeIDAndCursor(
+		t,
+		api,
+		envelopeTestUtils.DefaultClientEnvelopeNodeId,
+		&envelopes.Cursor{
+			NodeIdToSequenceId: map[uint32]uint64{
+				1600: 1,
+			},
 		},
-	})
+	)
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "DependsOn has not been seen by this node")
 }
diff --git a/pkg/api/message/service.go b/pkg/api/message/service.go
index 64a2c331..aabefefb 100644
--- a/pkg/api/message/service.go
+++ b/pkg/api/message/service.go
@@ -407,6 +407,14 @@ func (s *Service) validatePayerEnvelope(
 		return nil, err
 	}
 
+	if payerEnv.TargetOriginator != s.registrant.NodeID() {
+		return nil, status.Errorf(codes.InvalidArgument, "invalid target originator")
+	}
+
+	if _, err = payerEnv.RecoverSigner(); err != nil {
+		return nil, err
+	}
+
 	if err := s.validateClientInfo(&payerEnv.ClientEnvelope); err != nil {
 		return nil, err
 	}
@@ -444,10 +452,6 @@ func (s *Service) validateKeyPackage(
 
 func (s *Service) validateClientInfo(clientEnv *envelopes.ClientEnvelope) error {
 	aad := clientEnv.Aad()
-	// nolint:staticcheck
-	if aad.GetTargetOriginator() != s.registrant.NodeID() {
-		return status.Errorf(codes.InvalidArgument, "invalid target originator")
-	}
 
 	if !clientEnv.TopicMatchesPayload() {
 		return status.Errorf(codes.InvalidArgument, "topic does not match payload")
diff --git a/pkg/api/payer/nodeSelector.go b/pkg/api/payer/nodeSelector.go
index 043eb05f..29f8d793 100644
--- a/pkg/api/payer/nodeSelector.go
+++ b/pkg/api/payer/nodeSelector.go
@@ -10,7 +10,7 @@ import (
 )
 
 type NodeSelectorAlgorithm interface {
-	GetNode(topic topic.Topic) (uint32, error)
+	GetNode(topic topic.Topic, banlist ...[]uint32) (uint32, error)
 }
 
 type StableHashingNodeSelectorAlgorithm struct {
@@ -30,7 +30,10 @@ func HashKey(topic topic.Topic) uint32 {
 }
 
 // GetNode selects a node for a given topic using stable hashing
-func (s *StableHashingNodeSelectorAlgorithm) GetNode(topic topic.Topic) (uint32, error) {
+func (s *StableHashingNodeSelectorAlgorithm) GetNode(
+	topic topic.Topic,
+	banlist ...[]uint32,
+) (uint32, error) {
 	nodes, err := s.reg.GetNodes()
 	if err != nil {
 		return 0, err
@@ -60,5 +63,23 @@ func (s *StableHashingNodeSelectorAlgorithm) GetNode(topic topic.Topic) (uint32,
 		return topicHash < nodeLocations[i]
 	})
 
-	return nodes[idx%len(nodeLocations)].NodeID, nil
+	// Flatten banlist
+	banned := make(map[uint32]struct{})
+	for _, list := range banlist {
+		for _, id := range list {
+			banned[id] = struct{}{}
+		}
+	}
+
+	// Find the next available node
+	for i := 0; i < len(nodes); i++ {
+		candidateIdx := (idx + i) % len(nodeLocations)
+		candidateNodeID := nodes[candidateIdx].NodeID
+
+		if _, exists := banned[candidateNodeID]; !exists {
+			return candidateNodeID, nil
+		}
+	}
+
+	return 0, errors.New("no available nodes after considering banlist")
 }
diff --git a/pkg/api/payer/nodeSelector_test.go b/pkg/api/payer/nodeSelector_test.go
index 2cabdf69..3a397924 100644
--- a/pkg/api/payer/nodeSelector_test.go
+++ b/pkg/api/payer/nodeSelector_test.go
@@ -226,3 +226,40 @@ func TestGetNode_ConfirmTopicBalance(t *testing.T) {
 	}
 
 }
+
+func TestGetNode_NodeGetNextIfBanned(t *testing.T) {
+	mockRegistry := mocks.NewMockNodeRegistry(t)
+	mockRegistry.On("GetNodes").Return([]registry.Node{
+		{NodeID: 100},
+		{NodeID: 200},
+		{NodeID: 300},
+	}, nil)
+	tpc1 := *topic.NewTopic(topic.TOPIC_KIND_IDENTITY_UPDATES_V1, []byte("stable_key"))
+
+	selector := payer.NewStableHashingNodeSelectorAlgorithm(mockRegistry)
+
+	node1, err := selector.GetNode(tpc1)
+	require.NoError(t, err)
+	require.EqualValues(t, 200, node1)
+
+	banlist := []uint32{node1}
+
+	reselectedNode, err := selector.GetNode(tpc1, banlist)
+	require.NoError(t, err)
+	require.NotEqualValues(t, node1, reselectedNode)
+	require.EqualValues(t, 300, reselectedNode)
+
+	banlist = append(banlist, reselectedNode)
+
+	reselectedNode, err = selector.GetNode(tpc1, banlist)
+	require.NoError(t, err)
+	require.NotEqualValues(t, node1, reselectedNode)
+	require.EqualValues(t, 100, reselectedNode)
+
+	banlist = append(banlist, reselectedNode)
+
+	// now we are out of nodes to try
+	reselectedNode, err = selector.GetNode(tpc1, banlist)
+	require.Error(t, err)
+	require.EqualValues(t, 0, reselectedNode)
+}
diff --git a/pkg/api/payer/publish_test.go b/pkg/api/payer/publish_test.go
index 82f69c09..3373db2a 100644
--- a/pkg/api/payer/publish_test.go
+++ b/pkg/api/payer/publish_test.go
@@ -181,11 +181,14 @@ func TestPublishToNodes(t *testing.T) {
 		HttpAddress: formatAddress(originatorServer.Addr().String()),
 	}, nil)
 
+	mockRegistry.On("GetNodes").Return([]registry.Node{
+		{NodeID: 100},
+	}, nil)
+
 	groupId := testutils.RandomGroupID()
 	testGroupMessage := envelopesTestUtils.CreateGroupMessageClientEnvelope(
 		groupId,
 		[]byte("test message"),
-		100, // This is the expected originator ID of the test server
 	)
 
 	publishResponse, err := svc.PublishClientEnvelopes(
@@ -203,6 +206,8 @@ func TestPublishToNodes(t *testing.T) {
 	require.NoError(t, err)
 
 	targetTopic := parsedOriginatorEnvelope.UnsignedOriginatorEnvelope.PayerEnvelope.ClientEnvelope.TargetTopic()
-
 	require.Equal(t, targetTopic.Identifier(), groupId[:])
+
+	targetOriginator := parsedOriginatorEnvelope.UnsignedOriginatorEnvelope.PayerEnvelope.TargetOriginator
+	require.EqualValues(t, 100, targetOriginator)
 }
diff --git a/pkg/api/payer/service.go b/pkg/api/payer/service.go
index 4d9eca0d..92f84cd3 100644
--- a/pkg/api/payer/service.go
+++ b/pkg/api/payer/service.go
@@ -76,7 +76,7 @@ func (s *Service) PublishClientEnvelopes(
 	// For each originator found in the request, publish all matching envelopes to the node
 	for originatorId, payloadsWithIndex := range grouped.forNodes {
 		s.log.Info("publishing to originator", zap.Uint32("originator_id", originatorId))
-		originatorEnvelopes, err := s.publishToNodes(ctx, originatorId, payloadsWithIndex)
+		originatorEnvelopes, err := s.publishToNodeWithRetry(ctx, originatorId, payloadsWithIndex)
 		if err != nil {
 			s.log.Error("error publishing payer envelopes", zap.Error(err))
 			return nil, status.Error(codes.Internal, "error publishing payer envelopes")
@@ -165,6 +165,42 @@ func (s *Service) groupEnvelopes(
 	return &out, nil
 }
 
+func (s *Service) publishToNodeWithRetry(
+	ctx context.Context,
+	originatorID uint32,
+	indexedEnvelopes []clientEnvelopeWithIndex,
+) ([]*envelopesProto.OriginatorEnvelope, error) {
+	var banlist []uint32
+	var result []*envelopesProto.OriginatorEnvelope
+	var err error
+	var nodeID = originatorID
+
+	topic := indexedEnvelopes[0].payload.TargetTopic()
+
+	for retries := 0; retries < 5; retries++ {
+		result, err = s.publishToNodes(ctx, nodeID, indexedEnvelopes)
+		if err == nil {
+			return result, nil
+		}
+
+		s.log.Error(
+			"error publishing to node. Retrying with the next one",
+			zap.Uint32("failed_node", nodeID),
+			zap.Error(err),
+		)
+
+		// Add failed node to banlist and retry
+		banlist = append(banlist, nodeID)
+
+		nodeID, err = s.nodeSelector.GetNode(topic, banlist)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return nil, err
+}
+
 func (s *Service) publishToNodes(
 	ctx context.Context,
 	originatorID uint32,
@@ -177,7 +213,7 @@ func (s *Service) publishToNodes(
 	}
 	client := message_api.NewReplicationApiClient(conn)
 
-	payerEnvelopes, err := s.signAllClientEnvelopes(indexedEnvelopes)
+	payerEnvelopes, err := s.signAllClientEnvelopes(originatorID, indexedEnvelopes)
 	if err != nil {
 		return nil, status.Errorf(codes.Internal, "error signing payer envelopes: %v", err)
 	}
@@ -199,7 +235,7 @@ func (s *Service) publishToBlockchain(
 	targetTopic := clientEnvelope.TargetTopic()
 	identifier := targetTopic.Identifier()
 	desiredOriginatorId := uint32(1) //TODO: determine this from the chain
-	desiredSequenceId := uint64(0)
+	var desiredSequenceId uint64
 	kind := targetTopic.Kind()
 
 	// Get the group ID as [32]byte
@@ -296,7 +332,10 @@ func (s *Service) publishToBlockchain(
 		desiredSequenceId,
 	)
 	if err != nil {
-		return nil, err
+		s.log.Error(
+			"Chosen node for cursor check is unreachable",
+			zap.Uint32("targetNodeId", targetNodeId),
+		)
 	}
 
 	return &envelopesProto.OriginatorEnvelope{
@@ -324,12 +363,12 @@ func buildUnsignedOriginatorEnvelopeFromChain(
 	}
 }
 
-func (s *Service) signAllClientEnvelopes(
+func (s *Service) signAllClientEnvelopes(originatorID uint32,
 	indexedEnvelopes []clientEnvelopeWithIndex,
 ) ([]*envelopesProto.PayerEnvelope, error) {
 	out := make([]*envelopesProto.PayerEnvelope, len(indexedEnvelopes))
 	for i, indexedEnvelope := range indexedEnvelopes {
-		envelope, err := s.signClientEnvelope(indexedEnvelope.payload)
+		envelope, err := s.signClientEnvelope(originatorID, indexedEnvelope.payload)
 		if err != nil {
 			return nil, err
 		}
@@ -338,7 +377,7 @@ func (s *Service) signAllClientEnvelopes(
 	return out, nil
 }
 
-func (s *Service) signClientEnvelope(
+func (s *Service) signClientEnvelope(originatorID uint32,
 	clientEnvelope *envelopes.ClientEnvelope,
 ) (*envelopesProto.PayerEnvelope, error) {
 	envelopeBytes, err := clientEnvelope.Bytes()
@@ -346,7 +385,7 @@ func (s *Service) signClientEnvelope(
 		return nil, err
 	}
 
-	payerSignature, err := utils.SignClientEnvelope(envelopeBytes, s.payerPrivateKey)
+	payerSignature, err := utils.SignClientEnvelope(originatorID, envelopeBytes, s.payerPrivateKey)
 	if err != nil {
 		return nil, err
 	}
@@ -356,6 +395,7 @@ func (s *Service) signClientEnvelope(
 		PayerSignature: &associations.RecoverableEcdsaSignature{
 			Bytes: payerSignature,
 		},
+		TargetOriginator: originatorID,
 	}, nil
 }
 
diff --git a/pkg/constants/constants.go b/pkg/constants/constants.go
index ce6d5df2..46d881ec 100644
--- a/pkg/constants/constants.go
+++ b/pkg/constants/constants.go
@@ -3,6 +3,7 @@ package constants
 const (
 	JWT_DOMAIN_SEPARATION_LABEL        = "jwt|"
 	PAYER_DOMAIN_SEPARATION_LABEL      = "payer|"
+	TARGET_ORIGINATOR_SEPARATION_LABEL = "target|"
 	ORIGINATOR_DOMAIN_SEPARATION_LABEL = "originator|"
 	NODE_AUTHORIZATION_HEADER_NAME     = "node-authorization"
 	MAX_BLOCKCHAIN_ORIGINATOR_ID       = 100
diff --git a/pkg/envelopes/envelopes_test.go b/pkg/envelopes/envelopes_test.go
index 9d7a7711..99844171 100644
--- a/pkg/envelopes/envelopes_test.go
+++ b/pkg/envelopes/envelopes_test.go
@@ -19,7 +19,7 @@ func TestValidOriginatorEnvelope(t *testing.T) {
 	originatorSequenceId := uint64(1)
 
 	clientEnv := envelopeTestUtils.CreateClientEnvelope()
-	payerEnvelope := envelopeTestUtils.CreatePayerEnvelope(t, clientEnv)
+	payerEnvelope := envelopeTestUtils.CreatePayerEnvelope(t, originatorNodeId, clientEnv)
 	originatorEnvelope := envelopeTestUtils.CreateOriginatorEnvelope(
 		t,
 		originatorNodeId,
@@ -48,7 +48,7 @@ func TestSerialize(t *testing.T) {
 	originatorSequenceId := uint64(1)
 
 	clientEnv := envelopeTestUtils.CreateClientEnvelope()
-	payerEnvelope := envelopeTestUtils.CreatePayerEnvelope(t, clientEnv)
+	payerEnvelope := envelopeTestUtils.CreatePayerEnvelope(t, originatorNodeId, clientEnv)
 	originatorEnvelope := envelopeTestUtils.CreateOriginatorEnvelope(
 		t,
 		originatorNodeId,
@@ -138,10 +138,12 @@ func TestPayloadType(t *testing.T) {
 }
 
 func TestRecoverSigner(t *testing.T) {
+	nodeId := envelopeTestUtils.DefaultClientEnvelopeNodeId
 	payerPrivateKey := testutils.RandomPrivateKey(t)
-	rawPayerEnv := envelopeTestUtils.CreatePayerEnvelope(t)
+	rawPayerEnv := envelopeTestUtils.CreatePayerEnvelope(t, nodeId)
 
 	payerSignature, err := utils.SignClientEnvelope(
+		nodeId,
 		rawPayerEnv.UnsignedClientEnvelope,
 		payerPrivateKey,
 	)
@@ -159,6 +161,7 @@ func TestRecoverSigner(t *testing.T) {
 
 	// Now test with an incorrect signature
 	wrongPayerSignature, err := utils.SignClientEnvelope(
+		nodeId,
 		testutils.RandomBytes(128),
 		payerPrivateKey,
 	)
diff --git a/pkg/envelopes/payer.go b/pkg/envelopes/payer.go
index 13cf638f..83125a25 100644
--- a/pkg/envelopes/payer.go
+++ b/pkg/envelopes/payer.go
@@ -12,8 +12,9 @@ import (
 )
 
 type PayerEnvelope struct {
-	proto          *envelopesProto.PayerEnvelope
-	ClientEnvelope ClientEnvelope
+	proto            *envelopesProto.PayerEnvelope
+	ClientEnvelope   ClientEnvelope
+	TargetOriginator uint32
 }
 
 func NewPayerEnvelope(proto *envelopesProto.PayerEnvelope) (*PayerEnvelope, error) {
@@ -25,7 +26,11 @@ func NewPayerEnvelope(proto *envelopesProto.PayerEnvelope) (*PayerEnvelope, erro
 	if err != nil {
 		return nil, err
 	}
-	return &PayerEnvelope{proto: proto, ClientEnvelope: *clientEnv}, nil
+	return &PayerEnvelope{
+		proto:            proto,
+		ClientEnvelope:   *clientEnv,
+		TargetOriginator: proto.GetTargetOriginator(),
+	}, nil
 }
 
 func (p *PayerEnvelope) Proto() *envelopesProto.PayerEnvelope {
@@ -46,7 +51,7 @@ func (p *PayerEnvelope) RecoverSigner() (*common.Address, error) {
 		return nil, errors.New("payer signature is missing")
 	}
 
-	hash := utils.HashPayerSignatureInput(p.proto.UnsignedClientEnvelope)
+	hash := utils.HashPayerSignatureInput(p.proto.TargetOriginator, p.proto.UnsignedClientEnvelope)
 	signer, err := ethcrypto.SigToPub(hash, payerSignature.Bytes)
 	if err != nil {
 		return nil, err
diff --git a/pkg/indexer/e2e_test.go b/pkg/indexer/e2e_test.go
index 2e4232d4..e4739c18 100644
--- a/pkg/indexer/e2e_test.go
+++ b/pkg/indexer/e2e_test.go
@@ -62,9 +62,9 @@ func TestStoreMessages(t *testing.T) {
 
 	message := testutils.RandomBytes(78)
 	groupID := testutils.RandomGroupID()
-	topic := topic.NewTopic(topic.TOPIC_KIND_GROUP_MESSAGES_V1, groupID[:]).Bytes()
+	msgTopic := topic.NewTopic(topic.TOPIC_KIND_GROUP_MESSAGES_V1, groupID[:]).Bytes()
 
-	clientEnvelope := envelopesTestUtils.CreateGroupMessageClientEnvelope(groupID, message, 0)
+	clientEnvelope := envelopesTestUtils.CreateGroupMessageClientEnvelope(groupID, message)
 	clientEnvelopeBytes, err := proto.Marshal(clientEnvelope)
 	require.NoError(t, err)
 
@@ -77,7 +77,7 @@ func TestStoreMessages(t *testing.T) {
 		results, err := querier.SelectGatewayEnvelopes(
 			context.Background(),
 			queries.SelectGatewayEnvelopesParams{
-				Topics: [][]byte{topic},
+				Topics: [][]byte{msgTopic},
 			},
 		)
 		require.NoError(t, err)
@@ -91,7 +91,7 @@ func TestStoreMessages(t *testing.T) {
 			firstEnvelope.OriginatorEnvelope,
 		)
 		require.NoError(t, err)
-		require.Equal(t, firstEnvelope.Topic, topic)
+		require.Equal(t, firstEnvelope.Topic, msgTopic)
 
 		return true
 	}, 5*time.Second, 100*time.Millisecond, "Failed to find indexed envelope")
diff --git a/pkg/indexer/storer/groupMessage_test.go b/pkg/indexer/storer/groupMessage_test.go
index 6e82ef6a..f164eae5 100644
--- a/pkg/indexer/storer/groupMessage_test.go
+++ b/pkg/indexer/storer/groupMessage_test.go
@@ -49,7 +49,7 @@ func TestStoreGroupMessages(t *testing.T) {
 	message := testutils.RandomBytes(30)
 	sequenceID := uint64(1)
 
-	clientEnvelope := envelopesTestUtils.CreateGroupMessageClientEnvelope(groupID, message, 0)
+	clientEnvelope := envelopesTestUtils.CreateGroupMessageClientEnvelope(groupID, message)
 
 	logMessage := testutils.BuildMessageSentLog(t, groupID, clientEnvelope, sequenceID)
 	var err error
@@ -92,7 +92,7 @@ func TestStoreGroupMessageDuplicate(t *testing.T) {
 	message := testutils.RandomBytes(30)
 	sequenceID := uint64(1)
 
-	clientEnvelope := envelopesTestUtils.CreateGroupMessageClientEnvelope(groupID, message, 0)
+	clientEnvelope := envelopesTestUtils.CreateGroupMessageClientEnvelope(groupID, message)
 
 	logMessage := testutils.BuildMessageSentLog(t, groupID, clientEnvelope, sequenceID)
 
diff --git a/pkg/proto/openapi/xmtpv4/message_api/message_api.swagger.json b/pkg/proto/openapi/xmtpv4/message_api/message_api.swagger.json
index 9e15df25..1b29f962 100644
--- a/pkg/proto/openapi/xmtpv4/message_api/message_api.swagger.json
+++ b/pkg/proto/openapi/xmtpv4/message_api/message_api.swagger.json
@@ -203,6 +203,10 @@
         },
         "payerSignature": {
           "$ref": "#/definitions/associationsRecoverableEcdsaSignature"
+        },
+        "targetOriginator": {
+          "type": "integer",
+          "format": "int64"
         }
       },
       "title": "Wraps client envelope with payer signature"
diff --git a/pkg/proto/openapi/xmtpv4/message_api/misbehavior_api.swagger.json b/pkg/proto/openapi/xmtpv4/message_api/misbehavior_api.swagger.json
index f05c70ab..aa1f2d7e 100644
--- a/pkg/proto/openapi/xmtpv4/message_api/misbehavior_api.swagger.json
+++ b/pkg/proto/openapi/xmtpv4/message_api/misbehavior_api.swagger.json
@@ -130,6 +130,10 @@
         },
         "payerSignature": {
           "$ref": "#/definitions/associationsRecoverableEcdsaSignature"
+        },
+        "targetOriginator": {
+          "type": "integer",
+          "format": "int64"
         }
       },
       "title": "Wraps client envelope with payer signature"
diff --git a/pkg/proto/xmtpv4/envelopes/envelopes.pb.go b/pkg/proto/xmtpv4/envelopes/envelopes.pb.go
index 9b9e24ad..04a10881 100644
--- a/pkg/proto/xmtpv4/envelopes/envelopes.pb.go
+++ b/pkg/proto/xmtpv4/envelopes/envelopes.pb.go
@@ -268,6 +268,7 @@ type PayerEnvelope struct {
 	state                  protoimpl.MessageState                  `protogen:"open.v1"`
 	UnsignedClientEnvelope []byte                                  `protobuf:"bytes,1,opt,name=unsigned_client_envelope,json=unsignedClientEnvelope,proto3" json:"unsigned_client_envelope,omitempty"` // Protobuf serialized
 	PayerSignature         *associations.RecoverableEcdsaSignature `protobuf:"bytes,2,opt,name=payer_signature,json=payerSignature,proto3" json:"payer_signature,omitempty"`
+	TargetOriginator       uint32                                  `protobuf:"varint,3,opt,name=target_originator,json=targetOriginator,proto3" json:"target_originator,omitempty"`
 	unknownFields          protoimpl.UnknownFields
 	sizeCache              protoimpl.SizeCache
 }
@@ -316,6 +317,13 @@ func (x *PayerEnvelope) GetPayerSignature() *associations.RecoverableEcdsaSignat
 	return nil
 }
 
+func (x *PayerEnvelope) GetTargetOriginator() uint32 {
+	if x != nil {
+		return x.TargetOriginator
+	}
+	return 0
+}
+
 // For blockchain envelopes, these fields are set by the smart contract
 type UnsignedOriginatorEnvelope struct {
 	state                protoimpl.MessageState `protogen:"open.v1"`
@@ -586,7 +594,7 @@ var file_xmtpv4_envelopes_envelopes_proto_rawDesc = string([]byte{
 	0x69, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x2e, 0x49, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79,
 	0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x48, 0x00, 0x52, 0x0e, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69,
 	0x74, 0x79, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x42, 0x09, 0x0a, 0x07, 0x70, 0x61, 0x79, 0x6c,
-	0x6f, 0x61, 0x64, 0x22, 0xa9, 0x01, 0x0a, 0x0d, 0x50, 0x61, 0x79, 0x65, 0x72, 0x45, 0x6e, 0x76,
+	0x6f, 0x61, 0x64, 0x22, 0xd6, 0x01, 0x0a, 0x0d, 0x50, 0x61, 0x79, 0x65, 0x72, 0x45, 0x6e, 0x76,
 	0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x38, 0x0a, 0x18, 0x75, 0x6e, 0x73, 0x69, 0x67, 0x6e, 0x65,
 	0x64, 0x5f, 0x63, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x5f, 0x65, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70,
 	0x65, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x16, 0x75, 0x6e, 0x73, 0x69, 0x67, 0x6e, 0x65,
@@ -596,59 +604,61 @@ var file_xmtpv4_envelopes_envelopes_proto_rawDesc = string([]byte{
 	0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x2e, 0x61, 0x73, 0x73, 0x6f, 0x63, 0x69, 0x61,
 	0x74, 0x69, 0x6f, 0x6e, 0x73, 0x2e, 0x52, 0x65, 0x63, 0x6f, 0x76, 0x65, 0x72, 0x61, 0x62, 0x6c,
 	0x65, 0x45, 0x63, 0x64, 0x73, 0x61, 0x53, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65, 0x52,
-	0x0e, 0x70, 0x61, 0x79, 0x65, 0x72, 0x53, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65, 0x22,
-	0xf2, 0x01, 0x0a, 0x1a, 0x55, 0x6e, 0x73, 0x69, 0x67, 0x6e, 0x65, 0x64, 0x4f, 0x72, 0x69, 0x67,
-	0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x2c,
-	0x0a, 0x12, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x6e, 0x6f, 0x64,
-	0x65, 0x5f, 0x69, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0d, 0x52, 0x10, 0x6f, 0x72, 0x69, 0x67,
-	0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x4e, 0x6f, 0x64, 0x65, 0x49, 0x64, 0x12, 0x34, 0x0a, 0x16,
-	0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x73, 0x65, 0x71, 0x75, 0x65,
-	0x6e, 0x63, 0x65, 0x5f, 0x69, 0x64, 0x18, 0x02, 0x20, 0x01, 0x28, 0x04, 0x52, 0x14, 0x6f, 0x72,
-	0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x53, 0x65, 0x71, 0x75, 0x65, 0x6e, 0x63, 0x65,
-	0x49, 0x64, 0x12, 0x23, 0x0a, 0x0d, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72,
-	0x5f, 0x6e, 0x73, 0x18, 0x03, 0x20, 0x01, 0x28, 0x03, 0x52, 0x0c, 0x6f, 0x72, 0x69, 0x67, 0x69,
-	0x6e, 0x61, 0x74, 0x6f, 0x72, 0x4e, 0x73, 0x12, 0x4b, 0x0a, 0x0e, 0x70, 0x61, 0x79, 0x65, 0x72,
-	0x5f, 0x65, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x18, 0x04, 0x20, 0x01, 0x28, 0x0b, 0x32,
-	0x24, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x65, 0x6e,
-	0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x2e, 0x50, 0x61, 0x79, 0x65, 0x72, 0x45, 0x6e, 0x76,
-	0x65, 0x6c, 0x6f, 0x70, 0x65, 0x52, 0x0d, 0x70, 0x61, 0x79, 0x65, 0x72, 0x45, 0x6e, 0x76, 0x65,
-	0x6c, 0x6f, 0x70, 0x65, 0x22, 0x3c, 0x0a, 0x0f, 0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x63, 0x68, 0x61,
-	0x69, 0x6e, 0x50, 0x72, 0x6f, 0x6f, 0x66, 0x12, 0x29, 0x0a, 0x10, 0x74, 0x72, 0x61, 0x6e, 0x73,
-	0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x5f, 0x68, 0x61, 0x73, 0x68, 0x18, 0x01, 0x20, 0x01, 0x28,
-	0x0c, 0x52, 0x0f, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x48, 0x61,
-	0x73, 0x68, 0x22, 0xa0, 0x02, 0x0a, 0x12, 0x4f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f,
-	0x72, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x40, 0x0a, 0x1c, 0x75, 0x6e, 0x73,
-	0x69, 0x67, 0x6e, 0x65, 0x64, 0x5f, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72,
-	0x5f, 0x65, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52,
-	0x1a, 0x75, 0x6e, 0x73, 0x69, 0x67, 0x6e, 0x65, 0x64, 0x4f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61,
-	0x74, 0x6f, 0x72, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x6a, 0x0a, 0x14, 0x6f,
-	0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x73, 0x69, 0x67, 0x6e, 0x61, 0x74,
-	0x75, 0x72, 0x65, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x35, 0x2e, 0x78, 0x6d, 0x74, 0x70,
-	0x2e, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x2e, 0x61, 0x73, 0x73, 0x6f, 0x63, 0x69,
-	0x61, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x2e, 0x52, 0x65, 0x63, 0x6f, 0x76, 0x65, 0x72, 0x61, 0x62,
-	0x6c, 0x65, 0x45, 0x63, 0x64, 0x73, 0x61, 0x53, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65,
-	0x48, 0x00, 0x52, 0x13, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x53, 0x69,
-	0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65, 0x12, 0x53, 0x0a, 0x10, 0x62, 0x6c, 0x6f, 0x63, 0x6b,
-	0x63, 0x68, 0x61, 0x69, 0x6e, 0x5f, 0x70, 0x72, 0x6f, 0x6f, 0x66, 0x18, 0x03, 0x20, 0x01, 0x28,
-	0x0b, 0x32, 0x26, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e,
-	0x65, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x2e, 0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x63,
-	0x68, 0x61, 0x69, 0x6e, 0x50, 0x72, 0x6f, 0x6f, 0x66, 0x48, 0x00, 0x52, 0x0f, 0x62, 0x6c, 0x6f,
-	0x63, 0x6b, 0x63, 0x68, 0x61, 0x69, 0x6e, 0x50, 0x72, 0x6f, 0x6f, 0x66, 0x42, 0x07, 0x0a, 0x05,
-	0x70, 0x72, 0x6f, 0x6f, 0x66, 0x42, 0xd3, 0x01, 0x0a, 0x19, 0x63, 0x6f, 0x6d, 0x2e, 0x78, 0x6d,
-	0x74, 0x70, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x65, 0x6e, 0x76, 0x65, 0x6c, 0x6f,
-	0x70, 0x65, 0x73, 0x42, 0x0e, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x50, 0x72,
-	0x6f, 0x74, 0x6f, 0x50, 0x01, 0x5a, 0x30, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f,
-	0x6d, 0x2f, 0x78, 0x6d, 0x74, 0x70, 0x2f, 0x78, 0x6d, 0x74, 0x70, 0x64, 0x2f, 0x70, 0x6b, 0x67,
-	0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x2f, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2f, 0x65, 0x6e,
-	0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0xa2, 0x02, 0x03, 0x58, 0x58, 0x45, 0xaa, 0x02, 0x15,
-	0x58, 0x6d, 0x74, 0x70, 0x2e, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x45, 0x6e, 0x76, 0x65,
-	0x6c, 0x6f, 0x70, 0x65, 0x73, 0xca, 0x02, 0x15, 0x58, 0x6d, 0x74, 0x70, 0x5c, 0x58, 0x6d, 0x74,
-	0x70, 0x76, 0x34, 0x5c, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0xe2, 0x02, 0x21,
-	0x58, 0x6d, 0x74, 0x70, 0x5c, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x5c, 0x45, 0x6e, 0x76, 0x65,
-	0x6c, 0x6f, 0x70, 0x65, 0x73, 0x5c, 0x47, 0x50, 0x42, 0x4d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74,
-	0x61, 0xea, 0x02, 0x17, 0x58, 0x6d, 0x74, 0x70, 0x3a, 0x3a, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34,
-	0x3a, 0x3a, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x62, 0x06, 0x70, 0x72, 0x6f,
-	0x74, 0x6f, 0x33,
+	0x0e, 0x70, 0x61, 0x79, 0x65, 0x72, 0x53, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65, 0x12,
+	0x2b, 0x0a, 0x11, 0x74, 0x61, 0x72, 0x67, 0x65, 0x74, 0x5f, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e,
+	0x61, 0x74, 0x6f, 0x72, 0x18, 0x03, 0x20, 0x01, 0x28, 0x0d, 0x52, 0x10, 0x74, 0x61, 0x72, 0x67,
+	0x65, 0x74, 0x4f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x22, 0xf2, 0x01, 0x0a,
+	0x1a, 0x55, 0x6e, 0x73, 0x69, 0x67, 0x6e, 0x65, 0x64, 0x4f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61,
+	0x74, 0x6f, 0x72, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x2c, 0x0a, 0x12, 0x6f,
+	0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x6e, 0x6f, 0x64, 0x65, 0x5f, 0x69,
+	0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0d, 0x52, 0x10, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61,
+	0x74, 0x6f, 0x72, 0x4e, 0x6f, 0x64, 0x65, 0x49, 0x64, 0x12, 0x34, 0x0a, 0x16, 0x6f, 0x72, 0x69,
+	0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x73, 0x65, 0x71, 0x75, 0x65, 0x6e, 0x63, 0x65,
+	0x5f, 0x69, 0x64, 0x18, 0x02, 0x20, 0x01, 0x28, 0x04, 0x52, 0x14, 0x6f, 0x72, 0x69, 0x67, 0x69,
+	0x6e, 0x61, 0x74, 0x6f, 0x72, 0x53, 0x65, 0x71, 0x75, 0x65, 0x6e, 0x63, 0x65, 0x49, 0x64, 0x12,
+	0x23, 0x0a, 0x0d, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x6e, 0x73,
+	0x18, 0x03, 0x20, 0x01, 0x28, 0x03, 0x52, 0x0c, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74,
+	0x6f, 0x72, 0x4e, 0x73, 0x12, 0x4b, 0x0a, 0x0e, 0x70, 0x61, 0x79, 0x65, 0x72, 0x5f, 0x65, 0x6e,
+	0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x18, 0x04, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x24, 0x2e, 0x78,
+	0x6d, 0x74, 0x70, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x65, 0x6e, 0x76, 0x65, 0x6c,
+	0x6f, 0x70, 0x65, 0x73, 0x2e, 0x50, 0x61, 0x79, 0x65, 0x72, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f,
+	0x70, 0x65, 0x52, 0x0d, 0x70, 0x61, 0x79, 0x65, 0x72, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70,
+	0x65, 0x22, 0x3c, 0x0a, 0x0f, 0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x63, 0x68, 0x61, 0x69, 0x6e, 0x50,
+	0x72, 0x6f, 0x6f, 0x66, 0x12, 0x29, 0x0a, 0x10, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74,
+	0x69, 0x6f, 0x6e, 0x5f, 0x68, 0x61, 0x73, 0x68, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x0f,
+	0x74, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x48, 0x61, 0x73, 0x68, 0x22,
+	0xa0, 0x02, 0x0a, 0x12, 0x4f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x45, 0x6e,
+	0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x40, 0x0a, 0x1c, 0x75, 0x6e, 0x73, 0x69, 0x67, 0x6e,
+	0x65, 0x64, 0x5f, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x65, 0x6e,
+	0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x1a, 0x75, 0x6e,
+	0x73, 0x69, 0x67, 0x6e, 0x65, 0x64, 0x4f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72,
+	0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x12, 0x6a, 0x0a, 0x14, 0x6f, 0x72, 0x69, 0x67,
+	0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x5f, 0x73, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65,
+	0x18, 0x02, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x35, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x2e, 0x69, 0x64,
+	0x65, 0x6e, 0x74, 0x69, 0x74, 0x79, 0x2e, 0x61, 0x73, 0x73, 0x6f, 0x63, 0x69, 0x61, 0x74, 0x69,
+	0x6f, 0x6e, 0x73, 0x2e, 0x52, 0x65, 0x63, 0x6f, 0x76, 0x65, 0x72, 0x61, 0x62, 0x6c, 0x65, 0x45,
+	0x63, 0x64, 0x73, 0x61, 0x53, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75, 0x72, 0x65, 0x48, 0x00, 0x52,
+	0x13, 0x6f, 0x72, 0x69, 0x67, 0x69, 0x6e, 0x61, 0x74, 0x6f, 0x72, 0x53, 0x69, 0x67, 0x6e, 0x61,
+	0x74, 0x75, 0x72, 0x65, 0x12, 0x53, 0x0a, 0x10, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x63, 0x68, 0x61,
+	0x69, 0x6e, 0x5f, 0x70, 0x72, 0x6f, 0x6f, 0x66, 0x18, 0x03, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x26,
+	0x2e, 0x78, 0x6d, 0x74, 0x70, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x65, 0x6e, 0x76,
+	0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x2e, 0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x63, 0x68, 0x61, 0x69,
+	0x6e, 0x50, 0x72, 0x6f, 0x6f, 0x66, 0x48, 0x00, 0x52, 0x0f, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x63,
+	0x68, 0x61, 0x69, 0x6e, 0x50, 0x72, 0x6f, 0x6f, 0x66, 0x42, 0x07, 0x0a, 0x05, 0x70, 0x72, 0x6f,
+	0x6f, 0x66, 0x42, 0xd3, 0x01, 0x0a, 0x19, 0x63, 0x6f, 0x6d, 0x2e, 0x78, 0x6d, 0x74, 0x70, 0x2e,
+	0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x65, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73,
+	0x42, 0x0e, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x50, 0x72, 0x6f, 0x74, 0x6f,
+	0x50, 0x01, 0x5a, 0x30, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x78,
+	0x6d, 0x74, 0x70, 0x2f, 0x78, 0x6d, 0x74, 0x70, 0x64, 0x2f, 0x70, 0x6b, 0x67, 0x2f, 0x70, 0x72,
+	0x6f, 0x74, 0x6f, 0x2f, 0x78, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2f, 0x65, 0x6e, 0x76, 0x65, 0x6c,
+	0x6f, 0x70, 0x65, 0x73, 0xa2, 0x02, 0x03, 0x58, 0x58, 0x45, 0xaa, 0x02, 0x15, 0x58, 0x6d, 0x74,
+	0x70, 0x2e, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x2e, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70,
+	0x65, 0x73, 0xca, 0x02, 0x15, 0x58, 0x6d, 0x74, 0x70, 0x5c, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34,
+	0x5c, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0xe2, 0x02, 0x21, 0x58, 0x6d, 0x74,
+	0x70, 0x5c, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x5c, 0x45, 0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70,
+	0x65, 0x73, 0x5c, 0x47, 0x50, 0x42, 0x4d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61, 0xea, 0x02,
+	0x17, 0x58, 0x6d, 0x74, 0x70, 0x3a, 0x3a, 0x58, 0x6d, 0x74, 0x70, 0x76, 0x34, 0x3a, 0x3a, 0x45,
+	0x6e, 0x76, 0x65, 0x6c, 0x6f, 0x70, 0x65, 0x73, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 })
 
 var (
diff --git a/pkg/server/server_test.go b/pkg/server/server_test.go
index 41aab841..aac1b60a 100644
--- a/pkg/server/server_test.go
+++ b/pkg/server/server_test.go
@@ -154,6 +154,7 @@ func TestCreateServer(t *testing.T) {
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{envelopeTestUtils.CreatePayerEnvelope(
 				t,
+				nodeId1,
 				envelopeTestUtils.CreateClientEnvelope(&envelopes.AuthenticatedData{
 					TargetOriginator: &nodeId1,
 					TargetTopic:      targetTopic,
@@ -168,6 +169,7 @@ func TestCreateServer(t *testing.T) {
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{envelopeTestUtils.CreatePayerEnvelope(
 				t,
+				nodeId2,
 				envelopeTestUtils.CreateClientEnvelope(&envelopes.AuthenticatedData{
 					TargetOriginator: &nodeId2,
 					TargetTopic:      targetTopic,
@@ -259,10 +261,10 @@ func TestReadOwnWritesGuarantee(t *testing.T) {
 		&message_api.PublishPayerEnvelopesRequest{
 			PayerEnvelopes: []*envelopes.PayerEnvelope{envelopeTestUtils.CreatePayerEnvelope(
 				t,
+				nodeId1,
 				envelopeTestUtils.CreateClientEnvelope(&envelopes.AuthenticatedData{
-					TargetOriginator: &nodeId1,
-					TargetTopic:      targetTopic,
-					DependsOn:        &envelopes.Cursor{},
+					TargetTopic: targetTopic,
+					DependsOn:   &envelopes.Cursor{},
 				}),
 			)},
 		},
diff --git a/pkg/testutils/envelopes/envelopes.go b/pkg/testutils/envelopes/envelopes.go
index 810652b6..71eafa2a 100644
--- a/pkg/testutils/envelopes/envelopes.go
+++ b/pkg/testutils/envelopes/envelopes.go
@@ -1,6 +1,8 @@
 package testutils
 
 import (
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/xmtp/xmtpd/pkg/utils"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -11,6 +13,8 @@ import (
 	"google.golang.org/protobuf/proto"
 )
 
+const DefaultClientEnvelopeNodeId = uint32(100)
+
 func UnmarshalUnsignedOriginatorEnvelope(
 	t *testing.T,
 	bytes []byte,
@@ -25,7 +29,7 @@ func UnmarshalUnsignedOriginatorEnvelope(
 }
 
 func CreateClientEnvelope(aad ...*envelopes.AuthenticatedData) *envelopes.ClientEnvelope {
-	nodeId := uint32(100)
+	nodeId := DefaultClientEnvelopeNodeId
 	if len(aad) == 0 {
 		aad = append(aad, &envelopes.AuthenticatedData{
 			TargetOriginator: &nodeId,
@@ -43,13 +47,11 @@ func CreateClientEnvelope(aad ...*envelopes.AuthenticatedData) *envelopes.Client
 func CreateGroupMessageClientEnvelope(
 	groupID [32]byte,
 	message []byte,
-	targetOriginator uint32,
 ) *envelopes.ClientEnvelope {
 	return &envelopes.ClientEnvelope{
 		Aad: &envelopes.AuthenticatedData{
 			TargetTopic: topic.NewTopic(topic.TOPIC_KIND_GROUP_MESSAGES_V1, groupID[:]).
 				Bytes(),
-			TargetOriginator: &targetOriginator,
 		},
 		Payload: &envelopes.ClientEnvelope_GroupMessage{
 			GroupMessage: &mlsv1.GroupMessageInput{
@@ -81,6 +83,7 @@ func CreateIdentityUpdateClientEnvelope(
 
 func CreatePayerEnvelope(
 	t *testing.T,
+	nodeID uint32,
 	clientEnv ...*envelopes.ClientEnvelope,
 ) *envelopes.PayerEnvelope {
 	if len(clientEnv) == 0 {
@@ -89,9 +92,18 @@ func CreatePayerEnvelope(
 	clientEnvBytes, err := proto.Marshal(clientEnv[0])
 	require.NoError(t, err)
 
+	key, err := crypto.GenerateKey()
+	require.NoError(t, err)
+
+	payerSignature, err := utils.SignClientEnvelope(nodeID, clientEnvBytes, key)
+	require.NoError(t, err)
+
 	return &envelopes.PayerEnvelope{
 		UnsignedClientEnvelope: clientEnvBytes,
-		PayerSignature:         &associations.RecoverableEcdsaSignature{},
+		PayerSignature: &associations.RecoverableEcdsaSignature{
+			Bytes: payerSignature,
+		},
+		TargetOriginator: nodeID,
 	}
 }
 
@@ -102,7 +114,7 @@ func CreateOriginatorEnvelope(
 	payerEnv ...*envelopes.PayerEnvelope,
 ) *envelopes.OriginatorEnvelope {
 	if len(payerEnv) == 0 {
-		payerEnv = append(payerEnv, CreatePayerEnvelope(t))
+		payerEnv = append(payerEnv, CreatePayerEnvelope(t, originatorNodeID))
 	}
 
 	unsignedEnv := &envelopes.UnsignedOriginatorEnvelope{
@@ -127,7 +139,7 @@ func CreateOriginatorEnvelopeWithTopic(
 	originatorSequenceID uint64,
 	topic []byte,
 ) *envelopes.OriginatorEnvelope {
-	payerEnv := CreatePayerEnvelope(t, CreateClientEnvelope(
+	payerEnv := CreatePayerEnvelope(t, originatorNodeID, CreateClientEnvelope(
 		&envelopes.AuthenticatedData{
 			TargetTopic:      topic,
 			TargetOriginator: &originatorNodeID,
diff --git a/pkg/utils/hash.go b/pkg/utils/hash.go
index 75d0886b..bc6fc396 100644
--- a/pkg/utils/hash.go
+++ b/pkg/utils/hash.go
@@ -1,12 +1,17 @@
 package utils
 
 import (
+	"encoding/binary"
 	ethcrypto "github.com/ethereum/go-ethereum/crypto"
 	"github.com/xmtp/xmtpd/pkg/constants"
 )
 
-func HashPayerSignatureInput(unsignedClientEnvelope []byte) []byte {
+func HashPayerSignatureInput(originatorID uint32, unsignedClientEnvelope []byte) []byte {
+	targetBytes := make([]byte, 4)
+	binary.BigEndian.PutUint32(targetBytes, originatorID)
 	return ethcrypto.Keccak256(
+		[]byte(constants.TARGET_ORIGINATOR_SEPARATION_LABEL),
+		targetBytes,
 		[]byte(constants.PAYER_DOMAIN_SEPARATION_LABEL),
 		unsignedClientEnvelope,
 	)
diff --git a/pkg/utils/signature.go b/pkg/utils/signature.go
index f4dc1360..5b072d01 100644
--- a/pkg/utils/signature.go
+++ b/pkg/utils/signature.go
@@ -7,10 +7,11 @@ import (
 )
 
 func SignClientEnvelope(
+	originatorID uint32,
 	unsignedClientEnvelope []byte,
 	payerPrivateKey *ecdsa.PrivateKey,
 ) ([]byte, error) {
-	hash := HashPayerSignatureInput(unsignedClientEnvelope)
+	hash := HashPayerSignatureInput(originatorID, unsignedClientEnvelope)
 	signature, err := ethcrypto.Sign(hash, payerPrivateKey)
 	if err != nil {
 		return nil, err