Looking even beyond the upcoming version 5.0, we can make some guesses and issue a few opinions on the future of Windows NT security. Windows NT domains with their one-step trust relationships suffer by comparison to other systems in large environments. We can expect some improvements here. We’ll see alternative authentication cryptosystems, like Kerberos (technologically outdated by well standardized), that shore up the already reasonably secure Windows NT mechanisms. And public-private key authentication is a wonderful sign. ACLs will probably not change much, and we’ll always be wanting more sophisticated audit analysis tools. The "nets" are becoming even more important and extending even further into our work-a-day worlds. There are three ways to counter networking security threats: encryption, encryption, and encryption. Publicly available cryptography has made more progress in the last few years thanks to the Internet than the two decades preceding. With U.S. government bending slightly on its 40-bit key export restrictions, we are close to having all the strong public/private and symmetric key cryptosystems we need. The secret now is to practically implement them, and with today’s schemes it all depends on the "certificates" of the public/private key cryptosystems. If we can weave an effective certificate infrastructure, the problem of en route attacks on information is essentially solved. Microsoft will concentrate much of its cryptographic attention on Windows NT, and once we can cryptographically protect from network "taps" and readily manage certificates, most of our networking concerns will be minimized. However, our Trojan Horse threat is worse than ever. In the long run, increased security for Windows NT and all other commercial systems depends on their ability to limit the capabilities that "programs" – in their myriad forms – gain regardless who runs them. While good operational practice helps, it’s not fully reliable. Features for limiting what such programs can do is important to long-range security. But most of all, security comes as much from administrative diligence as from operating system features. You simply must take the time to learn the basics and carefully plan your environment. Inspect it frequently, and give "tape-on-the-safe" the minor importance it deserves. Sort through the hype and keep your ear to the ground. Security is yours to use or lose, and Windows NT is a decent place to make your stand.