Internet Security--A Plan of Attack

"The biggest pitfall," Slotnick warns, "is to think of security as different from, and not tightly integrated with, the entire site. Security systems must be tied to the site at the most fundamental, elemental levels, usually beginning with the database schema design. Security cannot be thought of as separate from overall site reliability, performance and scalability. Security cannot be bolted on. Adding it later is almost guaranteed to require a site redesign."