Remove net451 as a cross-compile target

.gitignore

@@ -36,4 +36,5 @@ node_modules
 **/[Cc]ompiler/[Rr]esources/**/*.js
 *launchSettings.json
 .build/
-.testPublish/
+.testPublish/
+global.json

src/Microsoft.AspNetCore.Antiforgery/Internal/CryptographyAlgorithms.cs

@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.Antiforgery.Internal
 
             return sha256;
         }
-#else
+#elif NET46
         public static SHA256 CreateSHA256()
         {
             SHA256 sha256;
@@ -33,6 +33,8 @@ namespace Microsoft.AspNetCore.Antiforgery.Internal
 
             return sha256;
         }
+#else
+#error target frameworks need to be updated.
 #endif
     }
 }

src/Microsoft.AspNetCore.Antiforgery/Microsoft.AspNetCore.Antiforgery.csproj

@@ -4,7 +4,7 @@
 
   <PropertyGroup>
     <Description>An antiforgery system for ASP.NET Core designed to generate and validate tokens to prevent Cross-Site Request Forgery attacks.</Description>
-    <TargetFrameworks>netstandard1.3;net451</TargetFrameworks>
+    <TargetFrameworks>netstandard1.3;net46</TargetFrameworks>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore;antiforgery</PackageTags>

test/Microsoft.AspNetCore.Antiforgery.Test/Internal/DefaultClaimUidExtractorTest.cs

@@ -60,7 +60,7 @@ namespace Microsoft.AspNetCore.Antiforgery.Internal
             identity.AddClaim(new Claim(ClaimTypes.Email, "someone@antifrogery.com"));
             identity.AddClaim(new Claim(ClaimTypes.GivenName, "some"));
             identity.AddClaim(new Claim(ClaimTypes.Surname, "one"));
-#if NET452
+#if NET46
             // CoreCLR doesn't support an 'empty' name
             identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, string.Empty));
 #elif NETCOREAPP2_0

test/Microsoft.AspNetCore.Antiforgery.Test/Microsoft.AspNetCore.Antiforgery.Test.csproj

@@ -3,7 +3,7 @@
   <Import Project="..\..\build\common.props" />
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0;net452</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net46</TargetFrameworks>
     <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netcoreapp2.0</TargetFrameworks>
   </PropertyGroup>
 
@@ -20,6 +20,7 @@
     <PackageReference Include="Microsoft.Extensions.WebEncoders" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="$(TestSdkVersion)" />
     <PackageReference Include="Moq" Version="$(MoqVersion)" />
+    <PackageReference Include="System.Security.Claims" Version="$(CoreFxVersion)" />
     <PackageReference Include="xunit.runner.visualstudio" Version="$(XunitVersion)" />
     <PackageReference Include="xunit" Version="$(XunitVersion)" />
   </ItemGroup>