Code and ciphers: Julius Caesar, the Enigma and the internet

Before leaving Vigenère try the following.
Problem 3.2
A message of 249 letters with Z used as space has been enciphered using a
Vigenère cipher. The text is
GLEKR DAKRD SHZIZ MUIOK RQSSJ MTAME ZIESO
YMAHB PLZBF DSHMW HHEXZ TAHZX YIGTA XZMUE
TSVXZ LRIML MYNEV OEELD TANXZ TMFEM GIRSB
RESJM LEMIV XEDBX MJONA HZLHG HSVWZ MUIZV
NWESJ MTAMI UVYMD LMTRH BJZMU ETSGL EKRDA
KRDAG MMNYV RIMRD NNZFE KMSFS CVIFR WZMUM
SSCVO HSDIL MMNSG LESNT PXAHI QMMNS GLILM
FOHX.
Find the key and decrypt the message.
How much text do we need to solve a Vigenère cipher?
In Example 3.1 we had 157 characters of cipher and a key of length 3 so
that we had over 50 characters from each cipher alphabet. With this much
text we found numerous repeated digraphs, some of which extended into
trigraphs and, rather luckily, one octograph. From these we were able to
find the key and decipher the message quite easily. A cipher text of 50
times the length of the key should, in general, be adequate to solve a
cipher of this type. The Vigenère system is therefore vulnerable under situation
(1) of Chapter 1. In situation (2), where the plain and cipher texts
are both available a text of length twice the length of the key would be sufficient.
Obviously, Vigenère ciphers cannot be recommended unless
either the messages are very short or the keys are very long.
Jefferson’s cylinder
Polyalphabetic systems 37
A simple device which provides a series of simple substitution alphabets
seems to have been constructed by Thomas Jefferson in the late eighteenth
century and subsequently re-invented by others. The device is
made of a set of numbered, physically identical, discs mounted on a
common axis about which they can be rotated independently. Each disc
has the alphabet in some shuffled order, probably different for each disc,
engraved on its periphery.
There could, in theory, be any number of discs in the set but there