Re: Cryptocard
Joel M Snyder <[email protected]>
| Newsgroups | gmane.comp.security.vpn |
|---|---|
| Organization | Opus One - +1 520 324 0494 |
| Message-ID | <[email protected]> |
>I don't know if cryptocard is >peer-to-peer or master-slave (Joel, can you answer >this for us, please?), but I would be nervous about a >master-slave setup if that's what it is. Yes, CryptoCard has the same style as Safeword---centralized knowledge, but distributed knowledge. In fact, I have had good experiences with Safeword as well in recent years (got a pile of tokens in front of me as I speak), but never used them in production because they don't support OpenVMS as a server. There is a human-factors issue with distributed servers and CryptoCard. CryptoCard is often used in "reduced input" mode, which means that the server keeps some state between queries; it lets the user avoid putting in the challenge if you (the network manager) don't want to require it. In essence, in reduced input mode, the token & the server kind of agree on what the challenge will be the next time, and the token shows it---if the server asks for the same challenge that the token is giving, then the user just presses ENTER instead of putting in the challenge. (for those of you who care, the next challenge is based on additional bits out of the encryption that the CryptoCard does but which are not displayed, so it is under control of the server, not some synchronized algorithm like SecurID uses.) If you flop around between servers, then you can't use reduced input (or, more precisely, the user will perceive that they always have to enter the challenge), so most people who use CryptoCard tend to have multiple servers, but the servers are ordered (i.e., failover, not active load sharing) so that the same card tends to hit the same server all the time. That doesn't mean you can't load balance them across regions, just that your users will be happier if you don't. So that's a long answer to the question. The short answer is "yes, you can have lots of servers." It's just that when you set it up, you need to be cognizant of the human interface issues related to the product as well as the IT reliability issues. But I would agree with Willie 100%: I like the idea that I don't have a single server which has the "core knowledge;" I can distribute the knowledge around by sharing the token's secret among a bunch of different servers using CryptoCard and that makes it more attractive to me. jms Joel M Snyder, 1404 East Lind Road, Tucson, AZ, 85719 Phone: +1 520 324 0494 x101 (v) +1 520 324 0495 (FAX) [email protected] http://www.opus1.com/jms Opus One