diff --git a/ClosedXML/ClosedXML.csproj b/ClosedXML/ClosedXML.csproj
index e761588..8b7e9cc 100644
--- a/ClosedXML/ClosedXML.csproj
+++ b/ClosedXML/ClosedXML.csproj
@@ -11,6 +11,8 @@
     <PackageLicenseUrl>https://github.com/ClosedXML/ClosedXML/blob/master/LICENSE</PackageLicenseUrl>
     <PackageProjectUrl>https://github.com/ClosedXML/ClosedXML</PackageProjectUrl>
     <RepositoryUrl>https://github.com/ClosedXML/ClosedXML</RepositoryUrl>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>ClosedXML.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
diff --git a/ClosedXML/Properties/AssemblyInfo.cs b/ClosedXML/Properties/AssemblyInfo.cs
index 79529f5..ddf1df5 100644
--- a/ClosedXML/Properties/AssemblyInfo.cs
+++ b/ClosedXML/Properties/AssemblyInfo.cs
@@ -1 +1 @@
-[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("ClosedXML_Tests")]
\ No newline at end of file
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("ClosedXML_Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100a1fb8ba59167fe734d64128ca73d32c45cb8a117246d09c95c8769db88fe332b0a3396bedd0ea48ee42b0e5796fec0798ca5cb628a9a6de80d35d6c67b936ca1670347b3d4f2b769c8ce2ddcf959dbac6bcd88e6c08751ea1fffa0522de3507193e7035305a8aa008d6c88cca1341b3120fa9c347ab3f97e2d772e2709277da5")]
diff --git a/ClosedXML_Examples/ClosedXML_Examples.csproj b/ClosedXML_Examples/ClosedXML_Examples.csproj
index 3cfbebd..3015018 100644
--- a/ClosedXML_Examples/ClosedXML_Examples.csproj
+++ b/ClosedXML_Examples/ClosedXML_Examples.csproj
@@ -3,6 +3,8 @@
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net40;net461</TargetFrameworks>
     <OutputType>Exe</OutputType>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>ClosedXML.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
diff --git a/ClosedXML_Tests/ClosedXML_Tests.csproj b/ClosedXML_Tests/ClosedXML_Tests.csproj
index d9eec23..aae1fea 100644
--- a/ClosedXML_Tests/ClosedXML_Tests.csproj
+++ b/ClosedXML_Tests/ClosedXML_Tests.csproj
@@ -7,6 +7,8 @@
 
   <PropertyGroup>
     <DefineConstants>$(AppVeyor)</DefineConstants>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>ClosedXML.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.0' ">