Simple C# API Program

I need a simple C# program written to perform an API call. I would like someone I can speak with on the phone so a well spoken English speaker. Preferabiliy I would like someone who knows Xamarin Forms as I might use you for other work. The coding must be done on my server as you will not have access to the URL as it’s not published to the internet. Here is how the authentication works. I will provide you with the encryption key and endpoint URL. · Authentication request made against the path /User/AccessCheck/Authenticate · HTTP Method – POST · Data (example) - iv=123456789&token=TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlz= Generating the token and iv values: · Generate an initialization vector (IV) for use in encryption - this becomes the iv value in the posted data · Build a string with authentication data in the following format username=test&password=test1234based on user supplied credentials · Encrypt the string using AES-128 with a pre-shared key and the previously generated IV value · The token value in the posted data is a Base64 encoding of the encryption results returns the member ID in the body and HTTP status code 200 OK if the login is successful. There will be no body if it's a failure and we will respond with HTTP status code 401 Unauthorized. Response body will be a JSON object with, at minimum, the following fields: { member: "", status: "", message: "" } HTTP status codes will also be used to indicate success/failure · 200 - Authentication success · 400 - Invalid request sent from client · 401 - Invalid username and/or password · 500 - Unable to process the request - server errors