diff --git a/OpenMcdf.Ole/IBinarySerializable.cs b/OpenMcdf.Ole/IBinarySerializable.cs
index b04e8a7..06a26b6 100644
--- a/OpenMcdf.Ole/IBinarySerializable.cs
+++ b/OpenMcdf.Ole/IBinarySerializable.cs
@@ -1,6 +1,6 @@
 namespace OpenMcdf.Ole;
 
-public interface IBinarySerializable
+internal interface IBinarySerializable
 {
     void Write(BinaryWriter bw);
     void Read(BinaryReader br);