I felt the same way when taking a look at Identity. It added lots of abstractions and does not suit with my case that I have legacy system which implemented own authentication work-flow. Tons of example about OWIN authentication which uses Identity and EF by default. But technically, you are able to strip out Identity to use only OWIN cookie aut…

authenticationWithAsp.netIdentity.cs

[HttpPost]
public ActionResult Login(LoginViewModel model, string returnUrl)
{
    var user = _userService.GetByEmail(model.Email);

    //check username and password from database, naive checking: password should be in SHA
    if (user != null && (user.Password == model.Password)) 
    {
        var claims = new[] {
                new Claim(ClaimTypes.Name, user.Name),
                new Claim(ClaimTypes.Email, user.Email),
                // can add more claims
            };

        var identity = new ClaimsIdentity(claims, "ApplicationCookie");

        // Add roles into claims
        var roles = _roleService.GetByUserId(user.Id).ToList();
        if (roles.Any())
        {
            var roleClaims = roles.Select(r => new Claim(ClaimTypes.Role, r.Name));
            identity.AddClaims(roleClaims);
        }

        var context = Request.GetOwinContext();
        var authManager = context.Authentication;

        authManager.SignIn(new AuthenticationProperties { IsPersistent = model.RememberMe }, identity);
        return RedirectToAction("Index", "Home");
    }
    // login failed.            
}

public ActionResult LogOut()
{
    var ctx = Request.GetOwinContext();
    var authManager = ctx.Authentication;

    authManager.SignOut("ApplicationCookie");
    return RedirectToAction("Login");
}