Works on IIS Express but does not work on IIS 10

[ramusbucket]

I ran your samples from Visual Studio 2019, while they worked with IIS Express. But when I deployed them on IIS on my local machine, decryption in .Net core application seems to be failing - "Error occurred during a cryptographic operation.".

This part seems to be returning null

   if (!CryptoUtil.BuffersAreEqual(
      buffer1: protectedData, buffer1Offset: ivByteCount + encryptedPayloadByteCount, buffer1Count: signatureByteCount,
      buffer2: computedSignature, buffer2Offset: 0, buffer2Count: computedSignature.Length))
  {

      // the computed signature didn't match the incoming signature, which is a sign of payload tampering
      return null;
  }

When I compared cookie generated from IIS Express and IIS, they are of different length. Could that be a problem?

One other thing I have is - I have machine keys generated on IIS which are same as what I'm using in IIS Express, basically, I'm using same keys as in repo samples. Any clue about why it doesn't work on IIS?

[ramusbucket]

This works, if the cookie is created with newest crypto routines (.Net Framework 4.5+).

For this to work, I have to add/update

• targetFramework to anything 4.5+ on httpRuntime element

• compatibilityMode="Framework45" on MachineKey element

  in web.config of Asp.Net Web Forms legacy application

and as I changed this there were errors for Unobtrusive validations which can be resolved by adding (this is optional) <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" /> to appSettings section.

Thank you for this good work @synercoder