Two Centuries On, a Cryptologist Cracks a Presidential Code | Hacker News Reader

Two Centuries On, a Cryptologist Cracks a Presidential Code

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71 pointssharksandwich11 comments

I'm no crypto expert, but I'm guessing nobody had previously cracked it because they hadn't really tried. By today's standards at least, it seems relatively straighforward.

I love how obviously human-generated the key is: "13, 34, 57, 65, 22, 78, 49." - the differences between the two digits are almost all 0, 1 or 2. As a species, we must really resent random numbers.

True, but 200 years ago random numbers were harder to come by.

You think they did not have some D10 and some D20? :)

As indicated by tetha's comment, that's not really true. Nature is a pretty good RNG. I was more amazed that someone who seems to have taken a keen interest in cryptography would not be concerned with generating good keys. Maybe I should expect that of someone who lived 200 years ago. I don't know.

(yes, the numbers could of course be truly random, but they don't seem it to me)

Just out of curiosity, what's your favorite technique for generating random numbers from nature? Let's say 7 numbers between 0 and 99.

They did have gambling back then. The roulette wheel came about in the 1800's, or they could have shuffled playing cards and drew some out of the deck, or thrown dice.

These aren't "natural" as in "from the earth", but they are trivial ways to calculate random numbers without assistance from a powered machine.

To answer your question though, I'd just flip a coin and calculate a random number in whatever range you want using binary.

With a Lava Lamp:

http://www.lavarnd.org/

Or with alpha-decay:

http://www.freepatentsonline.com/6745217.html

Either of those work well 200 years ago? I didn't think so.

The thing with feeding truly random numbers to a person is that they never seem "random enough," so you'll have people rejecting a stochastic process because they see patterns, so they'll go out of their way to make it look more like noise, and decreasing the entropy.

"Here be chaotic bits"

I love the idea of this. Commodity hardware + smarts = awesome

Random numbers are hard to generate even for computer, they have to based them on the system clock to generate a seed for a semi-random sequence.

So predictions of those sequences are not unheard of.

Truly random sequences are not has easy to get has it sounds :S

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