Validating Google ID tokens in C#

Question

I need to validate a Google ID token passed from a mobile device at my ASP.NET web api.

Google have some sample code here but it relies on a JWT NuGet package which is .

Answer 1

ClientId also needs to be passed, which should be set from Google API Console. If only pass TokenId, GoogleJsonWebSignature throws error. This answer is in addition to @edmundpie answer

var settings = new GoogleJsonWebSignature.ValidationSettings()
{
 Audience = new List() { "[Placeholder for Client Id].apps.googleusercontent.com" }
};

var validPayload = await GoogleJsonWebSignature.ValidateAsync(model.ExternalTokenId, settings);