X509Certificate2 certificate = TestCertificates.OAuthTestCertificate();

string requestUrl = "https://www.google.com/accounts/OAuthGetRequestToken";
string userAuthorizeUrl = "https://www.google.com/accounts/accounts/OAuthAuthorizeToken";
string accessUrl = "https://www.google.com/accounts/OAuthGetAccessToken";
string callBackUrl = "http://www.mysite.com/callback";

var consumerContext = new OAuthConsumerContext
{
	ConsumerKey = "weitu.googlepages.com",
	SignatureMethod = SignatureMethod.RsaSha1,
	Key = certificate.PrivateKey
};

var session = new OAuthSession(consumerContext, requestUrl, userAuthorizeUrl, accessUrl)
	.WithQueryParameters(new { scope = "http://www.google.com/m8/feeds" });

// get a request token from the provider
IToken requestToken = session.GetRequestToken();

// generate a user authorize url for this token (which you can use in a redirect from the current site)
string authorizationLink = session.GetUserAuthorizationUrlForToken(requestToken, callBackUrl);

// exchange a request token for an access token
IToken accessToken = session.ExchangeRequestTokenForAccessToken(requestToken);

// make a request for a protected resource
string responseText = session.Request().Get().ForUrl("http://www.google.com/m8/feeds/contacts/default/base").ToString();