Pages tagged cipher:

Two Centuries On, a Cryptologist Cracks a Presidential Code -

Interesting, though the codebreaker did use a computer to solve it.
200 anos depois um texto criptografado é decodificado. is available in the following editions and languages:
A cipher by Mr. Patterson. Simple to use without a computer, hard to crack.
For more than 200 years, buried deep within Thomas Jefferson's correspondence and papers, there lay a mysterious cipher -- a coded message that appears to have remained unsolved. Until now.