diff --git a/src/ExCSS.Tests/ExCSS.Tests.csproj b/src/ExCSS.Tests/ExCSS.Tests.csproj
index e6c73616..93b36e47 100644
--- a/src/ExCSS.Tests/ExCSS.Tests.csproj
+++ b/src/ExCSS.Tests/ExCSS.Tests.csproj
@@ -8,6 +8,8 @@
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
     <GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
     <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>ExCSS.Tests.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
   <ItemGroup>
@@ -20,6 +22,10 @@
     <PackageReference Include="xunit" Version="2.2.0" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Remove="ExCSS.Tests.snk" />
+  </ItemGroup>
+
   <ItemGroup>
     <Folder Include="Properties\" />
   </ItemGroup>
diff --git a/src/ExCSS.Tests/ExCSS.Tests.snk b/src/ExCSS.Tests/ExCSS.Tests.snk
new file mode 100644
index 00000000..056e8366
Binary files /dev/null and b/src/ExCSS.Tests/ExCSS.Tests.snk differ
diff --git a/src/ExCSS/ExCSS.csproj b/src/ExCSS/ExCSS.csproj
index e7a5494e..4ef0ca8a 100644
--- a/src/ExCSS/ExCSS.csproj
+++ b/src/ExCSS/ExCSS.csproj
@@ -13,8 +13,15 @@
 		<GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
 		<GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
 		<GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
+		<SignAssembly>true</SignAssembly>
+		<AssemblyOriginatorKeyFile>ExCSS.snk</AssemblyOriginatorKeyFile>
+		<Version>4.1.3</Version>
 	</PropertyGroup>
 
+	<ItemGroup>
+		<None Remove="ExCSS.snk" />
+	</ItemGroup>
+
 	<ItemGroup>
 		<Folder Include="Properties\" />
 	</ItemGroup>
diff --git a/src/ExCSS/ExCSS.snk b/src/ExCSS/ExCSS.snk
new file mode 100644
index 00000000..463621cb
Binary files /dev/null and b/src/ExCSS/ExCSS.snk differ
diff --git a/src/ExCSS/Properties/AssemblyInfo.cs b/src/ExCSS/Properties/AssemblyInfo.cs
index 0cfad6f3..0b5a9f5d 100644
--- a/src/ExCSS/Properties/AssemblyInfo.cs
+++ b/src/ExCSS/Properties/AssemblyInfo.cs
@@ -9,7 +9,7 @@
 [assembly: AssemblyCompany("")]
 [assembly: AssemblyProduct("ExCSS")]
 [assembly: AssemblyTrademark("")]
-[assembly: InternalsVisibleTo("ExCSS.Tests")]
+[assembly: InternalsVisibleTo("ExCSS.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100816d68fc780a643f4de3d073378928c09d763309e14aec27af5d9ce67f7bdcf824b9e82dbf4edd3d2f833c615aec1365d02d4fcab8997c1e1da83916369fcbe6f6d4574b5744790a3f05e617c5d2e74fc95c28e45ad962457b1535c9e0319e121be5d4d00133751b70408205ece1e8718a87e1829449d4926167e6063d2e06c8")]
 
 // Setting ComVisible to false makes the types in this assembly not visible
 // to COM components.  If you need to access a type in this assembly from