PolicyException when using DotNetOpenAuth library - asp.net

Question

When I drop the DotNetOpenAuth dll into my /bin directory, my app won't run with the following stack trace. Has anyone had any experience with this library? I've gone through their docs and suspect I'm not deploying it correctly. My web app should be running with full trust on my local machine, so it's unclear what permissions it's asking for that can't be acquired.
Thanks!
Tom
[PolicyException: Required permissions cannot be acquired.]
System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission) [phone]
System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission) +97
[FileLoadException: Could not load file or assembly 'DotNetOpenAuth, Version=3.3.1.9337, Culture=neutral, PublicKeyToken=2780ccd10d57b246' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0
System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +416
System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +166
System.Reflection.Assembly.Load(String assemblyString) +35
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +190
[ConfigurationErrorsException: Could not load file or assembly 'DotNetOpenAuth, Version=3.3.1.9337, Culture=neutral, PublicKeyToken=2780ccd10d57b246' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) [phone]
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +388
System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +232
System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +48
System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +210
System.Web.Compilation.BuildProvidersCompiler..ctor(VirtualPath configPath, Boolean supportLocalization, String outputAssemblyName) +76
System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed) [phone]
System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories) +185
System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +551
[HttpException (0x80004005): Could not load file or assembly 'DotNetOpenAuth, Version=3.3.1.9337, Culture=neutral, PublicKeyToken=2780ccd10d57b246' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +76
System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +1012
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters) +1025
[HttpException (0x80004005): Could not load file or assembly 'DotNetOpenAuth, Version=3.3.1.9337, Culture=neutral, PublicKeyToken=2780ccd10d57b246' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) [phone]
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +88
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4338644

Answer 1

Oddly, I found the solution was related to this.
The application pool identity has a
property called Load User Profile.
When this value is false, you may
receive the error shown above. To
resolve this, open IIS Manager and
navigate to your application pool
identity. You will find the setting in
the Advanced Settings window. Change
it to true.
I found that when I set it to true, the library began working again. When I flipped it back to false it continued to work even after service restarts and app pool recycles. So, strangely everything seems okay now.

Answer 2

It looks like Code Access Security does not consider DotNetOpenAuth to be loading with full trust. It only needs medium trust, actually, but here is the list of minimum permissions DotNetOpenAuth requests:
[assembly: SecurityPermission(SecurityAction.RequestMinimum, Execution = true)]
[assembly: WebPermission(SecurityAction.RequestMinimum, ConnectPattern = #"http://.*")]
[assembly: WebPermission(SecurityAction.RequestMinimum, ConnectPattern = #"https://.*")]
The second couple MAY be missing from some Medium trust configurations, but again if you're running with full trust it should be a non-issue.
Try adding <trust level="Full"/> to your web.config file in its <system.web> section and see if that either helps, or generates an error that will help you narrow down the problem.