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As standards become settled and vendors find ways to make their products interoperable, it is expected that many of the security technologies covered in the previous articles will be available and easy to use. They will be built into desktop operating systems and applications, and the way they function will be mostly invisible to the user.
Until then, the question is: What can I do to make my computing environment more secure? The way to start is to protect your password from theft.
Protecting your password involves the techniques described in the Windows on Computing Spring 1998 issue (www.washington.edu/computing/windows/issue21/password.html). It also means taking to heart such prudent suggestions as not sharing your password, not leaving it taped to your computer, changing it frequently, and not using a password that is easy-to-guess.
If you regularly exchange sensitive information or communicate across an untrusted network, you may want to consider acquiring a software suite for your desktop computer that will protect your password and other communication.
Two technologies--Secure Shell and Kerberos--are installed on the UW Uniform Access servers and, with some work on your part, can be used to encrypt your passwords or sessions.
Ssh employs an RSA public-key exchange during authentication to prevent passwords from traveling over the network as clear text. By authenticating both sides of the connection, ssh thwarts DNS (domain name system) spoofing attacks. A session key is also negotiated and is used to encrypt the entire communication, not just your password during authentication.
Ssh products are available for most mainstream operating systems including Unix, Windows, OS2, and MacOS. After installing ssh programs on your desktop, you will need to store your public key in your home directory on your Uniform Access account--as well as on your departmental and any other accounts you use--to enable RSA authentication to the UW central computers.
More information on ssh is available at www.ssh.fi/sshprotocols2/
The KDC manages a database of all known principals (people, services, printers, or hosts) in the network and their private keys. The private keys (usually passwords) are used to generate the encrypted tickets that are the basis of the authentication process used for any services that require authentication.
Kerberos services have been somewhat Unix-centric to date. More recently, version 5 of Kerberos is being used as the new authentication mechanism for the Windows NT 5 product line. Once that ships, which could be up to a year away, Microsoft plans to build Kerberos support for Windows 95 and 98. This would make Kerberos a much more viable option for use at the UW, with its large population. Until then, there are Kerberos-enabled applications available from third-party vendors that you might want to investigate.
Although using Kerberos for encrypted authentication now requires individual effort, when Kerberos is built into desktop operating systems and applications, much of the work will be done behind the scenes.
Kerberos can be used to just protect the password during authentication and the entire communication thereafter. Not all use of Kerberos encrypts the entire channel, so you may still be vulnerable to keystroke monitoring.
More details about Kerberos and how it works, links to MIT where Kerberos was first developed over a decade ago, plus additional information is available at gost.isi.edu/brian/security/kerberos.html
This initial use of Kerberos does not require any Kerberos software on the client side because Kerberos is only being used among systems in the C&C computer centers. That means, however, that passwords are still traveling across the network as clear text.
Also, if someone can gain access to your file system or your operating system, they may be able to steal your private keys (for example, your PGP key ring or ssh keys) or bypass Kerberos security by watching you type your password. These technologies are just part of security, not a solution to all security issues.
C&C is evaluating products, participating in setting standards, investigating what other universities are doing, and working on a scalable security architecture. There are still many questions, and no simple answers. Just about the time a protocol or product seems to be moving into position to be a viable solution to secure authentication, roadblocks are thrown up in the form of legal issues, standards recognition, cost, ease of use, and market share.
All of the solutions in use today have a fair amount of overhead associated with them because they require certificates, tickets, or key management. They also involve a fair amount of work by the user to set up and maintain his or her desktop environment. And, as the standards and vendor cooperation move slowly ahead, the technology keeps changing. New protocols emerge, causing us to rethink our entire approach yet again. So, the implementation of a university-wide solution will take a while.
In the meantime, each of us must determine what will meet our needs for the immediate future. The type of work you do and the people with whom you communicate may dictate the level of encryption you find necessary to use. Your local computer support person is your best resource for helping you consider which solutions may sufficiently address your needs today in your particular computing environment.