using System;
using System.Security;
using Microsoft.SharePoint.Client;

namespace SharePointOnlineAuthTest
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            const string serverRelativeUrl = "/site";
            const string userName = "user@vccqa.onmicrosoft.com";
            const string password = "password";

            using (var ctx = GetSharePointOnlineContext(serverRelativeUrl, userName, password))
            {
                var web = ctx.Web;
                ctx.Load(web);
                ctx.ExecuteQuery();

                Console.WriteLine(web.Title);
                Console.ReadLine();
            }
        }

        private static ClientContext GetSharePointOnlineContext(string serverRelativeUrl, string userName, string password)
        {
            var baseUri = new Uri("https://vccqa.sharepoint.com/");
            var siteUri = new Uri(baseUri, serverRelativeUrl);

            var securePassword = new SecureString();
            foreach (var c in password) securePassword.AppendChar(c);

            return new ClientContext(siteUri) {Credentials = new SharePointOnlineCredentials(userName, securePassword)};
        }
    }
}