Answers

• Yelinzh Member, Xamarin Team Xamurai

  February 2020 edited February 2020

  Cryptographic functions was introduced since .NET Standard target1.3. To use the library, add using System.Security.Cryptography above the class. ECDiffieHellman is an abstract class, you can use ECDiffieHellman.Create() method to get the instance.

  using System.Security.Cryptography;
  
  ...
  ECDiffieHellman cDiffieHellman = ECDiffieHellman.Create();
  

  Check the links:
  https://xamarinhelp.com/cryptography-in-xamarin-forms/
  https://stackoverflow.com/questions/41303777/use-ecdiffiehellman-with-or-without-cryptography-next-generation-cng

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• AlbertK MYMember ✭✭✭✭

  February 2020 edited February 2020

  I have the exact same code and it is deployed in Android 5 - API 21 physical hardware and I am getting the error below. The target framework is .net Standard 2.1. Can you or someone try on their end to see if you are getting the same error ?

  Xamarin 16.4.000.309 ([email protected])
  Xamarin Designer 16.4.0.475 (remotes/origin/[email protected])
  Xamarin.Android SDK 10.1.3.7 (d16-4/d66aed0)

  

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• Yelinzh Member, Xamarin Team Xamurai

  February 2020

  ECDiffieHellman is an abstract class try to create a custom class and make it inherit from ECDiffieHellman class to use the method. The PublicKey should be specified a value which will be used by this ECDiffieHellman instance.

  public class CustomClass : ECDiffieHellman
  {
      public override ECDiffieHellmanPublicKey PublicKey => throw new NotImplementedException();
  }
  

  Tutorial:
  https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.ecdiffiehellman.publickey?view=netcore-3.1

  0