Html.AntiForgeryToken helper throws exception on Mono

[Praburaj]

https://github.com/aspnet/Mvc/blob/dev/src/Microsoft.AspNet.Mvc.Core/AntiForgery/BinaryBlob.cs#L96

private static byte[] GenerateNewToken(int bitLength)
        {
            var data = new byte[bitLength / 8];
            CryptRand.FillBuffer(new ArraySegment<byte>(data));
            return data;
        }

System.DllNotFoundException: bcrypt.dll
  at (wrapper managed-to-native) Microsoft.AspNet.Security.DataProtection.UnsafeNativeMethods:BCryptGenRandom (intptr,byte*,uint,Microsoft.AspNet.Security.DataProtection.BCryptGenRandomFlags)
  at Microsoft.AspNet.Security.DataProtection.BCryptUtil.GenRandom (System.Byte* buffer, Int32 bufferBytes) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Security.DataProtection.CryptRand.FillBuffer (ArraySegment`1 buffer) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.BinaryBlob.GenerateNewToken (Int32 bitLength) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.BinaryBlob..ctor (Int32 bitLength) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.AntiForgeryToken.get_SecurityToken () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.TokenProvider.GenerateFormToken (Microsoft.AspNet.Http.HttpContext httpContext, System.Security.Claims.ClaimsIdentity identity, Microsoft.AspNet.Mvc.AntiForgeryToken cookieToken) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.AntiForgeryWorker.GetTokens (Microsoft.AspNet.Http.HttpContext httpContext, Microsoft.AspNet.Mvc.AntiForgeryToken oldCookieToken) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.AntiForgeryWorker.GetFormInputElement (Microsoft.AspNet.Http.HttpContext httpContext) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.AntiForgery.GetHtml (Microsoft.AspNet.Http.HttpContext context) [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.Rendering.HtmlHelper.AntiForgeryToken () [0x00000] in <filename unknown>:0 
  at ASP.Views_StoreManager_Edit_cshtml+<ExecuteAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.Razor.RazorView+<RenderPageCoreAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.Razor.RazorView+<RenderPageAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.Razor.RazorView+<RenderAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.ViewResult+<ExecuteResultAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.ReflectedActionInvoker+<InvokeActionResult>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.ReflectedActionInvoker+<InvokeActionResultFilter>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.ReflectedActionInvoker+<InvokeActionResultWithFilters>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.ReflectedActionInvoker+<InvokeActionAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Mvc.MvcRouteHandler+<RouteAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Routing.Template.TemplateRoute+<RouteAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Routing.RouteCollection+<RouteAsync>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at Microsoft.AspNet.Builder.RouterMiddleware+<Invoke>d__1.MoveNext () [0x00000] in <filename unknown>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at System.Runtime.CompilerServices.TaskAwaiter.GetResult () [0x00000] in <filename unknown>:0 
  at MusicStore.Startup+<<Configure>b__6>d__0.MoveNext () [0x00000] in <filename unknown>:0 

Recommendation from Levi:
MVC should instead be using the RandomNumberGenerator class. CryptRand was just a temporary workaround because the CLR team didn’t have the crypto libraries ported over.

[Praburaj]

@harshgMSFT

[yishaigalatzer]

@harshgMSFT please go ahead and make the change (preferably this week)

[harshgMSFT]

Prabu can you please verify and close?

[Praburaj]

This can be closed. If this is the same as the private that I tested, I can confirm this worked.