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From owner-traveller@Phaser.ShowCase.MPGN.COM Sat Sep 13 07:01:15 1997 To: traveller@MPGN.COM X-Original-Article-From: Scott Ellsworth <Scott_Ellsworth@alumni.hmc.edu> Subject: Re: Monetary Economics From: shadow@krypton.rain.com (Leonard Erickson) Message-ID: <970913.000519.9C4.rnr.w165w@krypton.rain.com> Date: Sat, 13 Sep 1997 00:05:19 PST In-Reply-To: <3.0.3.32.19970912130653.007c83c0@mail.deltanet.com> Organization: Shadownet X-Newsreader: rnr v2.20 Sender: owner-traveller@Phaser.ShowCase.MPGN.COM Reply-To: traveller@MPGN.COM
In mail you write:
For this to work, the entity doing the credit management needs to have the highest technology available, which I assume the Imperium has for a very long time. The techniques are likely known to those who want to find them out, because someone would have defected. Thus, you need a scheme that is robust, even knowing the algorithm and some of the keys.
Old rule of cryptology. No code/cipher is secure unless it can provide protection against someone who knows the algorithm, but not the key. This is because it is *inevitable* that the algorithm will either leak, or worse, be guessed.
If a key is known, that key is blown. But again, knowledge of one key should not compromise others. If it does, the code system is a piece of junk.
Theoretically, one time pads will *always* be secure. The only trouble is key distribution (well, key generation is tedious, but that's relatively minor).
Public key ciphers are subject to mathematical advances. Not *computational*, because if you have faster computers, then you can use bigger keys. But if someone comes up with a new mathematical technique that greatly decreases the work required to carry the mathematical operation that "secures" the cipher, then you are toast. For example, a whole bunch of public key schemes went down the tubes a few years back when somebody came up with a better solution to what's known as the "knapsack problem". The remaining schemes are based on the difficulty of factoring large numbers. So if a breakthrough is made in algorithms for factoring large numbers, they go away.
But for game purposes, we can assume that factoring is inherently hard (or that some new trick is found). So public key ciphers would be usable, though the keys may be a small book's worth of digits (stored in a tiny bit of storage).
Given the fact of there being higher tech cultures, one time pads will be used for military and diplomatic stuff as well as anything that you are afraid might be trouble if someone with higher tech shows up.
But for generic business purposes, you just use the highest TL available for the public key ciphering gear. That way, it's unlikely that anybody can crack things soon. Sure, if a TL 16 race is found, they can crack your ciphers in weeks instead of years, but they aren't likely to *bother* with most commercial stuff.
-- Leonard Erickson (aka Shadow) shadow@krypton.rain.com <--preferred leonard@qiclab.scn.rain.com <--last resort