History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
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History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
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Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#2Since he was using very uncommon symbols and the cipher is old, it's not so unlikely, that the author used a simple letter replacement table. Something like:
a -> #,
b -> *,
c -> =,
...
and so on. Unfortunately the handwriting is a bit messy and hard to read, but I'd try to make a frequency table for every symbol and compare that to a frequency table of letters in the english language:
http://en.wikipedia.org/wiki/Letter_frequency
Now try to replace the most frequent symbol with e, the second most frequent symbol with a or t and so on. Try some variations and look, if it makes any sense.
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#3[deleted]
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#4Since he was using very uncommon symbols and the cipher is old, it's not so unlikely, that the author used a simple letter replacement table. Something like: a -> #, b -> *, c -> =, ... and so on. Unfortunately the handwriting is a bit messy and hard to read, but I'd try to make a frequency table for every symbol and compare that to a frequency table of letters in the english language: http://en.wikipedia.org/wiki/Le…
If those pictures are the only coded messages letter frequency may not have enough ciphertext to run on reliably.
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#5[deleted]
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#6Since he was using very uncommon symbols and the cipher is old, it's not so unlikely, that the author used a simple letter replacement table. Something like: a -> #, b -> *, c -> =, ... and so on. Unfortunately the handwriting is a bit messy and hard to read, but I'd try to make a frequency table for every symbol and compare that to a frequency table of letters in the english language: http://en.wikipedia.org/wiki/Le…
If those pictures are the only coded messages letter frequency may not have enough ciphertext to run on reliably.
True, but that's why I'd try some variations.
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#7It's astonishing to me how little understanding people have of Unicode.
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#8Since he was using very uncommon symbols and the cipher is old, it's not so unlikely, that the author used a simple letter replacement table. Something like: a -> #, b -> *, c -> =, ... and so on. Unfortunately the handwriting is a bit messy and hard to read, but I'd try to make a frequency table for every symbol and compare that to a frequency table of letters in the english language: http://en.wikipedia.org/wiki/Le…
A simple substitution cipher is of course a good guess, but I suspect a homophonic one is more likely if the author knew anything about cryptography and thought it might come under attack. It's simple enough to come up with a number of homophones to complicate frequency analysis.
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#9It will take a major feat of cryptanalysis just to decipher the guy's handwriting, let alone the code parts.
Thanks for reminding me why I work with computers.
Re: History PhD Student Reaches out to Cryptographers to Help Break a Civil War Code
#10Since he was using very uncommon symbols and the cipher is old, it's not so unlikely, that the author used a simple letter replacement table. Something like: a -> #, b -> *, c -> =, ... and so on. Unfortunately the handwriting is a bit messy and hard to read, but I'd try to make a frequency table for every symbol and compare that to a frequency table of letters in the english language: http://en.wikipedia.org/wiki/Le…
A simple substitution cipher is of course a good guess, but I suspect a homophonic one is more likely if the author knew anything about cryptography and thought it might come under attack. It's simple enough to come up with a number of homophones to complicate frequency analysis.
> I suspect a homophonic one is more likely if the author knew anything about cryptography
How likely is it, that he had a deeper knowledge of cryptography in the 1860ies? But of course, if he had, it's still likely, that he used something more sophisticated.
http://en.wikipedia.org/wiki/History_of_cryptography#Cryptog...
Given the fact, that "12345" is still a common password in 2012, I would at least give it a shot. ;)