To
prove the importance of secure ciphers, here is the tragic story of Mary Queen
of Scots, who was foolish enough to use a weak cipher in the 16th century, long
after codebreakers had mastered frequency analysis.To
cut a long story short, Mary wanted to assassinate Queen Elizabeth I, and began
exchanging messages with her co-conspirators, in particular Anthony Babington.
This was dubbed the Babington Plot. Their messages were so treacherous that they
were enciphered, so that they could not be read if they fell into the wrong hands.
Here
you can see a mock-up of the letters that were sent between Mary Queen of Scots
and Anthony Babington.
The
cipher that Mary used is shown below. It has a cipher alphabet, with substitutions
for each letter from A to Z. The cipher also contains some code symbols for the
most common words, and some more sophisticated symbols. This mixture of codes
and ciphers is known as a nomenclator.
