1. Create an asp.net core project as usual and check if you have access using HTTPS. 
     dotnet new web -o Sample
 cd Sample
 dotnet restore
 dotnet run

    1.1. Navigate to https://localhost:5001. Can you read the message Hello World!? Congrats, you can stop reading this guide. If Firefox shows you a Secure Connection Failed message or you have an error message in console like this:

     dbug: HttpsConnectionAdapter[1]
 Failed to authenticate HTTPS connection.
 System.Security.Authentication.AuthenticationException: Authentication failed, see inner exception. ---> Interop+Crypto+OpenSslCryptographicException: error:2006D002:BIO routines:BIO_new_file:system lib

    Keep reading.

  2. Install ca-certificates and openssl packages

     sudo apt-get install ca-certificates openssl

  3. Genereate the .pfx certificate with dotnet command [1]

     dotnet dev-certs https -ep ${HOME}/.aspnet/https/aspnetapp.pfx -p crypticpassword

  4. Extract the .crt file [2]

     cd ${HOME}/.aspnet/https/
 openssl pkcs12 -in aspnetapp.pfx -nocerts -out aspnetapp.pfx
 openssl pkcs12 -in aspnetapp.pfx -clcerts -nokeys -out aspnetapp.crt

  5. Copy the .crt file to the certificates location [3]

     sudo cp aspnetapp.crt /usr/local/share/ca-certificates/

  6. Change the permissions to allow to read the certificate [4]

     sudo chmod +r /usr/local/share/ca-certificates/*

  7. Run the application again and check the https address

     dotnet run

Navigate to https://localhost:5001. If you have any error, you can check the links below to know more about each step.

References

[1] https://github.com/dotnet/dotnet-docker/blob/master/samples/aspnetapp/aspnetcore-docker-https.md

[2] https://www.markbrilman.nl/2011/08/howto-convert-a-pfx-to-a-seperate-key-crt-file/

[3] https://stackoverflow.com/a/44160125

[4] https://github.com/dotnet/cli/issues/9376#issuecomment-393954876