title: Validating Google ID tokens in C#
body: <p>I need to validate a Google ID token passed from a mobile device at my ASP.NET web api.</p>
  
  <p>Google have some sample code <a href="https://github.com/googleplus/gplus-verifytoken-csharp">here</a> but it relies on a JWT NuGet package which is .Net 4.5 only (I am using C#/.Net 4.0). Is anyone aware of any samples which do this without these packages or has achieved this themselves? The use of the package makes it very difficult to work out what I need to do without it.</p>