Cryptography Reference
In-Depth Information
1.3
The Middle Ages
All historians have insisted that the soundest education and training for po-
litical activity is the study of history, and that the surest and indeed the only way
to learn how to bear bravely the vicissitudes of fortune is to recall the disasters
of others.
Polybius (ca. 200-118 BC) , Greek historian and statesman
The Middle Ages refer to that period in Europe from roughly 500 to 1500
AD. (Historical scholars would put the end of the Middle Ages anywhere from
the end of the thirteenth to the fifteenth centuries since this is the beginning of
the Renaissance, but that depends on the area of Europe and other factors.) We
have already had an overlap with this period in Sections 1.1 and 1.2, wherein
we discussed, for instance, the runic stones dating back to the ninth century
AD, and the interest of the monks of the Middle Ages in ciphers inspired by the
Bible. Moreover, with the fall of the Roman empire, western Europe fell into
the Dark Ages (roughly 500-1000 AD), characterized by rampant illiteracy,
frequent warfare, and intellectual darkness, including the lack of any serious
development of cryptography. In Section 1.4, we will be able to fill in much of
the (non-European) time period with the contributions by the Arabs. For now
we begin with a philosopher of the thirteenth century.
Roger Bacon
Roger Bacon (1220-1292 AD) was a philosopher with the Franciscans whose
association began when he joined them in 1257. Among his interests were
alchemy, astronomy, languages, optics, and mathematics. He was truly a vision-
ary as evidenced by the fact that he considered the possibility of “flying ma-
chines”, “horseless carriages”, “motorboats”, “microscopes”, and “telescopes”
centuries before they were invented. Indeed he was one of the first medieval
advocates of experimental science. Our interest in him stems from his work,
Epistle on the Secret Works of Art and the Nullity of Magic , written around
1250. Seven simple ciphers are described therein. For instance, he suggests the
use of only consonants, or contrived symbols, and even shorthand. In fact he
wrote:
“A man is crazy who writes a secret in any other way than one which will
conceal it from the vulgar.”
Although it is a bit off the topic, it is worth mentioning the influence of Ba-
con's ideas, even after his death. Bacon believed in the existence of a habitable
land to the west by sea and in the Aristotelian view of a short westward pas-
sage to India. These ideas were repeated also, to the word, by Cardinal Pierre
d'Ailley, bishop of Cambrai (1350-1420) in his work Imago mundi , an ency-
clopedic world geography. A copy of this topic found its way into the hands
of Christopher Columbus, who was highly influenced by it. Columbus' copy is
now kept (with several hundred of his marginal comments) at the Biblioteca
Columbina, Seville, Spain. Now we turn to a story about the first European
text on cryptography.
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