[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*To*: jack <[email protected]>, [email protected]*Subject*: Re: Evolving algorithm for faster brute force key searches?*From*: [email protected] (Timothy C. May)*Date*: Sun, 22 Sep 1996 06:41:13 -0700*Cc*: [email protected]*Sender*: [email protected]

At 8:01 PM 7/5/96, jack wrote: >I got an idea last night, maybe this has already been thought of and >tried, but I thought I would give a quick outline of the program I was >thinking of: > >-Specify a maximum key size (assume 1024bits or something) >-Start with an arbitrary key "aaaaaaaaaaaaaa" > >Start a loop > >-create five mutations of the key >-use each key to try and decrypt a few bytes of the message >-run a (or some) statistical analysis tests and come up with a value >for how 'random' the decrypted bits are >-Pick the key that produced the least random ouput Schneier actually used my explanation of why this won't work in the Second Edition of his book. Basically, with any strong. modern cipher, there is no concept of "getting closer" to a solution. Thus, the "fitness landscape" for a brute-force-needed cipher looks like a flat plain (if portrayed in two dimensions), with the solution/key being a single-point spike rising from the plain. No hill-climber can find this spike except by landing right on it, which means evolutionary programming, genetic algorithms, simulated annealing, and neural net sorts of approaches are worthless. With some weak ciphers, this might work. I think Schneier makes some comments about who's looked at this. But weak ciphers are not too interesting. --Tim May We got computers, we're tapping phone lines, I know that that ain't allowed. ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, [email protected] 408-728-0152 | anonymous networks, digital pseudonyms, zero W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets, Higher Power: 2^1,257,787-1 | black markets, collapse of governments. "National borders aren't even speed bumps on the information superhighway."

**Follow-Ups**:**Re: Evolving algorithm for faster brute force key searches?***From:*Adam Shostack <[email protected]>

- Prev by Date:
**Spam from Timmy May (fart) and his merry band of mailbombers** - Next by Date:
**Re: Assassination Politics, was Kiddie porn on the Internet** - Prev by thread:
**Re: Spam from Timmy May (fart) and his merry band of mailbombers** - Next by thread:
**Re: Evolving algorithm for faster brute force key searches?** - Index(es):