diff --git a/pkg/pb/accountabilitypb/accountabilitypb.pb.go b/pkg/pb/accountabilitypb/accountabilitypb.pb.go
index c107ea919..67227f9c3 100644
--- a/pkg/pb/accountabilitypb/accountabilitypb.pb.go
+++ b/pkg/pb/accountabilitypb/accountabilitypb.pb.go
@@ -550,7 +550,7 @@ type FullCertificate struct {
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
-	Certificate map[uint64]*SignedPredecision `protobuf:"bytes,1,rep,name=certificate,proto3" json:"certificate,omitempty" protobuf_key:"varint,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
+	Certificate map[string]*SignedPredecision `protobuf:"bytes,1,rep,name=certificate,proto3" json:"certificate,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
 }
 
 func (x *FullCertificate) Reset() {
@@ -585,7 +585,7 @@ func (*FullCertificate) Descriptor() ([]byte, []int) {
 	return file_accountabilitypb_accountabilitypb_proto_rawDescGZIP(), []int{8}
 }
 
-func (x *FullCertificate) GetCertificate() map[uint64]*SignedPredecision {
+func (x *FullCertificate) GetCertificate() map[string]*SignedPredecision {
 	if x != nil {
 		return x.Certificate
 	}
@@ -733,7 +733,7 @@ var file_accountabilitypb_accountabilitypb_proto_rawDesc = []byte{
 	0x70, 0x65, 0x73, 0x2e, 0x4e, 0x6f, 0x64, 0x65, 0x49, 0x44, 0x52, 0x0b, 0x63, 0x65, 0x72, 0x74,
 	0x69, 0x66, 0x69, 0x63, 0x61, 0x74, 0x65, 0x1a, 0x63, 0x0a, 0x10, 0x43, 0x65, 0x72, 0x74, 0x69,
 	0x66, 0x69, 0x63, 0x61, 0x74, 0x65, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x12, 0x10, 0x0a, 0x03, 0x6b,
-	0x65, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x04, 0x52, 0x03, 0x6b, 0x65, 0x79, 0x12, 0x39, 0x0a,
+	0x65, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x03, 0x6b, 0x65, 0x79, 0x12, 0x39, 0x0a,
 	0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x23, 0x2e, 0x61,
 	0x63, 0x63, 0x6f, 0x75, 0x6e, 0x74, 0x61, 0x62, 0x69, 0x6c, 0x69, 0x74, 0x79, 0x70, 0x62, 0x2e,
 	0x53, 0x69, 0x67, 0x6e, 0x65, 0x64, 0x50, 0x72, 0x65, 0x64, 0x65, 0x63, 0x69, 0x73, 0x69, 0x6f,
diff --git a/pkg/pb/accountabilitypb/types/types.mir.go b/pkg/pb/accountabilitypb/types/types.mir.go
index 1045536a4..464056d7a 100644
--- a/pkg/pb/accountabilitypb/types/types.mir.go
+++ b/pkg/pb/accountabilitypb/types/types.mir.go
@@ -521,7 +521,7 @@ func FullCertificateFromPb(pb *accountabilitypb.FullCertificate) *FullCertificat
 		return nil
 	}
 	return &FullCertificate{
-		Certificate: types1.ConvertMap(pb.Certificate, func(k uint64, v *accountabilitypb.SignedPredecision) (types.NodeID, *SignedPredecision) {
+		Certificate: types1.ConvertMap(pb.Certificate, func(k string, v *accountabilitypb.SignedPredecision) (types.NodeID, *SignedPredecision) {
 			return (types.NodeID)(k), SignedPredecisionFromPb(v)
 		}),
 	}
@@ -533,8 +533,8 @@ func (m *FullCertificate) Pb() *accountabilitypb.FullCertificate {
 	}
 	pbMessage := &accountabilitypb.FullCertificate{}
 	{
-		pbMessage.Certificate = types1.ConvertMap(m.Certificate, func(k types.NodeID, v *SignedPredecision) (uint64, *accountabilitypb.SignedPredecision) {
-			return (uint64)(k), (v).Pb()
+		pbMessage.Certificate = types1.ConvertMap(m.Certificate, func(k types.NodeID, v *SignedPredecision) (string, *accountabilitypb.SignedPredecision) {
+			return (string)(k), (v).Pb()
 		})
 	}
 
diff --git a/protos/accountabilitypb/accountabilitypb.proto b/protos/accountabilitypb/accountabilitypb.proto
index 290140034..753d5ace6 100644
--- a/protos/accountabilitypb/accountabilitypb.proto
+++ b/protos/accountabilitypb/accountabilitypb.proto
@@ -79,7 +79,7 @@ message SignedPredecision {
 message FullCertificate {
   option (net.message) = true;
 
-  map<uint64,SignedPredecision> certificate = 1 [(mir.key_type) = "github.com/filecoin-project/mir/pkg/types.NodeID"];
+  map<string,SignedPredecision> certificate = 1 [(mir.key_type) = "github.com/filecoin-project/mir/pkg/types.NodeID"];
 }
 
 message InstanceParams {