To: Knighty Tin who wrote (34593 ) 10/27/1998 9:54:00 AM From: HB Read Replies (1) | Respond to of 132070
"If you can figure it out, then you know it's no good" Au contraire, mon frere. For most of us, if the algorithm and mode of operation are public knowledge, that makes it more secure. It will be an inviting target for cryptanalysts, many (though perhaps not the majority!) of whom will happily publish their breaks for the glory and professional prestige of having broken the thing (or on principle). If an algorithm has been public for a long time, especially if it is as widely used as is RSA, and no breaks have been published you can bet that a lot of smart people have spent a lot of effort trying to break it, and failed. (You can also bet that a lot of smart people who work for the NSA and the equivalents in other countries have tried to break it, and you are unlikely to ever know if they have failed or succeeded, but that's life.) The algorithm should still be good if you keep your key secret. If it's important to keep details of a cryptographic system, not just the keys, secret in order that it be secure, then it probably sucks. The exception might be the presumably secret algorithms employed by major governments. Presumably those are "public" enough within the agency that a large number of the world's best cryptographers spend a lot of time trying to crack them; presumably that's one thing these agencies spend a lot of their money on. So the total person-hours of top cryptanalytic effort expended on them is probably high enough that they can be considered more secure than the publicly available schemes. But they usually ain't for sale, and you don't wanna buy them even if they are -G-. The major reason these guys don't make the details public is probably not so much that it jeopardizes their security, but that it makes them available to adversaries (and in many cases, would probably reveals new cryptographic techniques unknown in public academic crypto circles). Of course, this is all PURE SPECULATION on my part. Using crypto from a private company that won't release details of the algorithm, and preferably the source code if it's software crypto, or the wiring diagram if it's hardware, is extremely risky: these bozos, or maybe they're certifiable geniuses, think it's safe, but you have no idea what it is, so you are quite right that you will never know if it's great stuff. The fact that it's not exposed to much cryptanalysis, however, makes it much less likely to be any good. (So even if they are geniuses, the people who wrote it are bozos if they trust it, too.) But perhaps, as an old MI spy, you have reasons for disagreeing that you'd care to share with us -G-. Disclaimer: I'm not an expert on this. In fact, I know nothink. I think the main RSA patent runs out in 2000; but the fact that their version has become standard in many applications is probably more important than the patents. With IMF funding getting a lot of flack, I guess the World Bank may be worried about its funding/reputation as well, during the Asian crisis. Now when the IMF starts underwriting NPR, things will have really gone wacky. Cheers, HB