public class CookieStore
{
    public static void SetCookie(string key, string value, TimeSpan expires)
    {
        HttpCookie encodedCookie = HttpSecureCookie.Encode(new HttpCookie(key, value));

        if (HttpContext.Current.Request.Cookies[key] != null)
        {
            var cookieOld = HttpContext.Current.Request.Cookies[key];
            cookieOld.Expires = DateTime.Now.Add(expires);
            cookieOld.Value = encodedCookie.Value;
            HttpContext.Current.Response.Cookies.Add(cookieOld);
        }
        else
        {
            encodedCookie.Expires = DateTime.Now.Add(expires);
            HttpContext.Current.Response.Cookies.Add(encodedCookie);
        }
     }
    public static string GetCookie(string key)
    {
        string value = string.Empty;
        HttpCookie cookie = HttpContext.Current.Request.Cookies[key];

        if (cookie != null)
        {
            // For security purpose, we need to encrypt the value.
            HttpCookie decodedCookie = HttpSecureCookie.Decode(cookie);
            value = decodedCookie.Value;
        }
        return value;
    }

}