RSACryptoServiceProvider.ExportParameters hangs on BWA

[rkttu]

Describe the bug

I tested a code which relies on RSACryptoServiceProvider.ExportParameters function in Blazor WebAssembly, but it hangs after the function called.

To Reproduce

I tested the below code in the SDK 3.1.300 (3.1.4 release).

private RSACryptoServiceProvider csp;
...
this.csp = new RSACryptoServiceProvider(keySize);
...
var parameters = csp.ExportParameters(true); // This line causes hang.
var parameters = csp.ExportParameters(false); // This line also causes hang.

Further technical details

• ASP.NET Core version: 3.2.0
• Include the output of dotnet --info

.NET Core SDK(global.json 반영):
 Version:   3.1.300
 Commit:    b2475c1295

런타임 환경:
 OS Name:     Windows
 OS Version:  10.0.19041
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.300\

Host (useful for support):
  Version: 3.1.4
  Commit:  0c2e69caa6

.NET Core SDKs installed:
  2.1.607 [C:\Program Files\dotnet\sdk]
  3.1.300 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version: Visual Studio 2019 v16.6.0, Windows 10 x64 19041.264, Microsoft Edge Stable Channel v81.0.416.77 x64

[ghost]

Tagging subscribers to this area: @bartonjs, @vcsjones, @krwq Notify danmosemsft if you want to be subscribed.

[davidfowl]

Likely a mono issue?

[shawnshaddock]

I'm having an issue with ExportParameters(true) as well. It takes an extremely long time to return, and when it finally does return the private parameters aren't there. Only Exponent and Modulus are populated.

[mdh1418]

Blazor WebAssembly in .NET 5 does not support cryptography libraries. It will throw System.PlatformNotSupportedException: System.Security.Cryptography is not supported on Browser.

[rkttu]

@davidfowl @mdh1418 Thanks for your comment. I understand that local cryptography in Blazor is a corner and rare use case. Also, it requires lots of computing resources. But I didn't find any notice or best practices about cryptographic API that does not support Blazor. This situation makes some confusion. If possible, even in the current version, this API should also throw the exception to prevent further trouble.

[rkttu]

For those of you interested in this topic, there is one piece of information I found. I found an alternative implementation. It will be an alternative implementation of built-in local cryptography.

https://github.com/ebekker/FMRL/tree/master/BlazorX.WebCrypto

https://github.com/BlazorExtensions/Home/issues/1