asp.net forms authentification security issues

I have a kind of asp.net forms authentication with the code like that:

FormsAuthent开发者_如何学编程ication.SetAuthCookie(account.Id.ToString(), true);
HttpContext.Current.User = new GenericPrincipal(new GenericIdentity(account.Id.ToString()), null);

What kind of additional efforts shall I take to make authentication cookie (that is user id) more securable? (https, encoding for example)

Thank you in advance!

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To get high security you should enable ssl in your web.config: