CRYPTOGRAPHY
Lecture 9
Language as a cipher
LANGUAGE
• A foreign language is a great cipher – if there
is no one who knows it.
• We will talk about 3 language ciphers
– Hieroglyphics (the Rosetta stone)
– Linear B
– The Navajo code talkers
The first 2 examples feature unintentional
encryption. The third example represents the
successful use of an obscure language in a military
setting.
Rosetta Stone
The Rosetta stone
For centuries, Hieroglyphics remained a
mystery. The earliest examples of
hieroglyphics date back to 3000 BCE and
were in use for the next 3500 years.
Hieroglyphs were ornate writings suitable for
temple and palace walls.
Hieratic was an everyday script, in which
every hieroglyph was replaced by a simpler
symbol, which was faster to write.
The Rosetta stone
In 600 BCE hieratic was replaced by an even
simpler script called demotic.
Hieroglyph, hieratic and demotic were three
versions of the same alphabet. Almost like
3 fonts.
All these fonts are phonetic (but we didn’t
know that for a while)
The Rosetta stone
These scripts were used for over 3000 years
by the ancient Egyptians for every aspect
of life. At the end of the fourth century
CE this script vanished. The last samples of
ancient Egyptian writing is seen in a temple
inscription on 394 CE and some demotic
graffiti has been dated to 450 CE.
The ancient Egyptian scripts were outlawed
by the Christian Church in order to
eradicate the link to Egypt’s pagan past.
The Rosetta stone
The ancient Egyptian scripts were replaced
by Coptic, a script consisting of the 24
letters of the Greek alphabet plus 6
demotic characters to represent uniquely
Egyptian sounds.
Coptic script dominated and the ancient
scripts were totally forgotten. The ancient
language evolved into a language which
became known as Coptic, but which was
wiped out in the 11th century by the spread
of Arabic. Any link to the past was lost.
The Rosetta stone
In the 17th century, a renewed interest in
hieroglyphs was awakened. But all attempts
to read the hieroglyphs were based on the
mistaken premise that the hieroglyphs were
semagrams – that each character
represented a complete idea.
No one was willing to accept or even consider
that the hieroglyphs were in fact
phonograms. The belief was that phonetic
spelling was too advanced for an ancient
civilization.
The Rosetta stone
The idea that hieroglyphs were picture
writing was strengthened by the fact that
even in the 1st century BCE, foreigners such
as Diodorus Siculus, a Greek historian,
described the hieroglyphs in terms
suggesting picture writing. A 17th century
German priest by the name of Athanasius
Kircher, an Egyptologist and cryptographer
who wrote a book on hieroglyphs, explaining
them as picture-words.
The Rosetta stone
The idea that hieroglyphs were picture
writing was strengthened by the fact that
even in the 1st century BCE, foreigners such
as Diodorus Siculus, a Greek historian,
described the hieroglyphs in terms
suggesting picture writing. A 17th century
German priest by the name of Athanasius
Kircher, an Egyptologist and cryptographer
who wrote a book on hieroglyphs, explaining
them as picture-words.
The Rosetta stone
So, we have a script corresponding to a dead
language. Can we decipher it?
No. If there is nothing to hold on to, we
cannot figure out what the script means.
The Rosetta stone
In 1798, Napoleon was busy invading Egypt.
Added to his military force were scientists,
historians and draftsmen.
In 1799, a slab was found in the town of
Rosetta which had writing on it in Greek,
demotic, and hieroglyphs.
The stone was taken to Cairo, then to
Alexandria. After the wars were over,
Britain obtained the Rosetta stone and it
moved to the British museum in 1802.
The
Rosetta
stone
The Rosetta stone
The Rosetta stone has the same
message on it in 3 different scripts.
Greek
Hieroglyphic
Demotic
The Rosetta stone
Two of which represent a language no
one had spoken for at least 8
centuries.
Even given the message in Greek, how
could that be used to explain the
message in Coptic or in ancient
Egyptian?
The Rosetta stone
Thomas Young was born in 1773. He was a child
prodigy, reading Greek, Latin, French, Italian,
hebrew, Chaldean, Syriac, Samaritan, Arabic,
Persian, Turkish, and Ethiopic by the age of 14.
He became fascinated by the Rosetta stone and
started studying it.
First he noticed a set of hieroglyphs surrounded
by a loop, called a cartouche. He thought that
this is looped because it represents something
(or more likely someone) important, probably
Ptolemy, the Pharaoh mentioned in the Greek.
Thomas Young
• Young repeated this process with another
cartouche he assumed was the queen
Berenika.
• He identified many of the 13 hieroglyphs
correctly.
• Then he stopped. He did not seem to be able
to accept that indeed hieroglyphs were
phonetic. He explained that the ones he
found were written phonetically because they
were Greek names, so they had no real
hieroglyph representation.
Jean-Francois Champollion
• In 1800, Champollion was 10 years old,
and was introduced to hieroglyphs by
Fourier.
• Fourier explained that no one could read
these hieroglyphs
• Champollion swore he would some day.
• In 1822, he applied Young’s approach to
other cartouches
Jean-Francois Champollion
Now Champollion had the phonetic meaning of
many hieroglyphs. A few more became clear
when he was looking at a cartouche that, given his
prior knowledge, could be deciphered as
AL?SE?TR?
Champollion was certain that this spelled
ALKSENTRS
that is, Alexandros or Alexander.
All these names were still foreign, perhaps
phonograms were only used for foreign names?
Champollion focused on a cartouche containing only 4
hieroglyphs.
The last two symbols were already known to
represent S. So the cartouche read ??SS
Now Champollion has a vast knowledge of languages
and although Coptic was a dead language, it was
fossilized in the liturgy of the Christian Coptic
Church, which Champollion was very familiar with.
What if the first symbol in the cartouche was a
semagram representing the sun. In Coptic, the sun
is RA. This would make the missing letter M and
the cartouche would read
RAMSS
The use of the semagram representing the sun is
an example of rebus writing, like
BEE + LEAF = BELIEF
But the big breakthrough was that the semagram
representing sun had to be read RA (not helio,
which would be the Greek)– which is the Coptic
word for SUN.
Now Champollion knew which language the
hieroglyphs were in, could identify everything else.
From then on, hieroglyphs could be read by
archeologists.
LINEAR B
More ancient languages
• After conquering hieroglyphs, archeologists
went on to decipher other ancient texts, such
as the Babylonian cuneiform and the Turkish
Kok-Turki runes, and the Brahmi alphabet of
India.
• Other scripts remain for which there are no
cribs (like cartouches)
• Linear B was a Cretan script dating back to
the Bronze age which was deciphered with no
crib.
More ancient languages
• After conquering hieroglyphs, archeologists
went on to decipher other ancient texts, such
as the Babylonian cuneiform and the Turkish
Kok-Turki runes, and the Brahmi alphabet of
India.
• Other scripts remain for which there are no
cribs (like cartouches)
• Linear B was a Cretan script dating back to
the Bronze age which was deciphered with no
crib.
Crete
Ancient Crete
• Sir Thomas Evans was interested in the
period of Greek history described by
Homer in the Illiad and the Odyssey.
• E.g. The Trojan war
• Some scholars dismissed these things as
legends, but in 1872 Heinrich
Schliemann uncovered the site of Troy,
close to the Western coast of Turkey.
Ancient Crete
• Between 1872 and 1900 more evidence
was discovered to show a rich Hellenic
period between 2800 and 1100 BCE
• On the Greek mainland, Mycenae was
the center of archeological finds.
However, no form of writing was found.
• Sir Arthur could not accept that such a
sophisticated society had no writing.
Ancient Crete
Sir Arthur found, through antiquities
dealers, seals originating from Crete,
particularly Knossos.
Knossos was home to the palace of the
king Minos, the center of an empire that
dominated the Aegean.
Sir Arthur set out for Crete and began
excavating.
Ancient Crete
The results were swift and spectacular.
He unearthed a large castle.
On March 31, Sir Arthur found a single
clay tablet with an inscription
A few days later, a wooden chest full of
inscribed clay tablets were found.
These tablets were baked by the fire
that destroyed the palace. They were
very clear and easy to read.
Ancient Crete
Three sets of tablets were found. The
third set was the most recent
The script on it was called Linear B.
Aside from not having a crib, the main
problem was that no one knew what
language linear B was in.
Linear B
Features of Linear B
• The direction of writing was left to right.
• There were 90 distinct characters:
– Purely alphabetic scripts have between 20-40
characters (We have 26, Russian has 36, Arabic
has 28)
– Semagram based languages have hundreds, or
thousands of characters (Chinese has over 5000)
– Syllabic alphabets have between 50 and 100.
• So the writing was syllabic
The language of Linear B
• The script looked like classical Cypriot script,
which was known to be a form of Greek script
used between 600 and 200 BCE
• But the most common final consonant in Greek
is s, and so the most common final character
should have been the corresponding in the
Cypriot script. This is found in linear B, but
not at the end of the word.
• The consensus was that the script of linear B
later evolved into the Cypriot script, but that
the language was not Greek.
The language of Linear B
• Sir Arthur Evans was adamantly set against
Linear B being Greek for another reason:
• Excavations showed the Minoan Empire to be a
powerful rival of the Mycenaeans, probably
the dominant rival, so it did not seems that
they would adopt the language used in
Mycenaea.
Classification of the characters
in Linear B
• Alice Kober, a classicist from Brooklyn colege
focused on the structure of the language.
She noticed that many words formed triplets,
it looked like the same word appearing in 3
slightly different forms. It looked that the
stem was identical, but there were different
endings. This suggests a highly inflective
language.
• She assigned to each sign a number, so that
even though she could not associate a phonetic
value to each sign, she figured out what the
relationships were.
Classification of the characters
in Linear B
• Each sign was a combination of a consonant
and a vowel sound. So you could have, e.g.
MI BI
MA BA
ME BE
MO BO
A table of these values would show you that a
certain character shared a vowel with another
character, or that two characters shared the
same consonant.
Alice Kober died of cancer before she could go
much further.
Cracking Linear B
• Michael Ventris wanted to crack linear B. He started
with Alice Kober’s discoveries.
• Each character is a CV combination, but what happens
if the vowel has to appear alone?
• He hypothesized that there must be some character
for when a vowel comes in the beginning of a word.
• He characterized all of these in a table.
• Then he saw the words 08-73-30-12, 70-52-12 and
69-53-12 appear over and over again. He guessed that
these must be the names of important cities. His
table showed the 08 was one of those characters
which only appear in the beginning of a word and
represent a vowel.
Cracking Linear B
• The only city known to begin with a vowel was Amnisos
so that 08-73-30-12 should be A – MI – NI –SO with
the final s missing.
• According to the table, this meant that 12, which
represented SO was in the same vowel column and the
seventh consonant row.
• Two other signs, 70 and 52, were in the same vowel
column, so they must end with an O sound too. Thus
the second city mentioned 70-52-12 so it must be ?O?0-SO
• What if this represented the city Knossos? Then we
have KO-NO-SO and we know 2 new consonant sounds
for the entire table. Also, since 30 and 52 were in
the same consonant row (N) this was a sign that he
was on the right track.
Cracking Linear B
• Next he looked at 69-53-12 = ??-?I-SO where 69
does not have the vowel I or the vowel O. The name
TU-LI-SO (Tulissos) suggested itself. Now he had 8
signs, and each one of those gave rise to many others,
because of the combination of vowels and consonants.
• Finally, he deciphered the final words on most columns
of figures, 05-31 as TO-SA and 05-12 as TO-SO,
similar to the Greek words for TOTAL:tossos and
tossa
• But this suggests that Linear B was Greek! He did not
accept that this could be true, but continued to
pursue this line of reasoning
Sounds
in
Linear B
Sounds in Linear B
• Using the table, he deciphered more words:
poimen (shepherd), kerameus (potter), etc.
• He also deciphered some phrases, with no
problems.
• He came to the conclusion that this must be a
form of ancient Greek.
• John Chadwick was an expert in ancient Greek
and joined in with Ventris. Together they
completely deciphered the script.
• Now linear B tablets could be read – history
revealed itself.
The Navajo code talkers
Language as cipher
• One of the key Ideas is that you can
only decipher a message in a language
you know.
• The Rosetta stone was helpful only
because the Coptic language was kept
alive in the Christian Coptic Church.
• Linear B could be deciphered because it
was in ancient Greek.
Language as cipher
• But if you don’t know the language, how
can you decipher the message?
• This was the idea behind one of the
most successful cryptographic
endeavours: the Navajo code talkers.
Navajo code talkers
• The Navajo Code Talkers, whose ranks exceed 400 during the
course of World War II in the Pacific Theater. Have been
credited with saving countless lives and hastening the end of the
war. The Code Talker's served in all six Marine divisions from
1942 to 1945.
• The Code Talker's primary job was to talk and transmit
information on tactics, troop movements, orders and other vital
battlefield information via telegraphs and radios in their native
dialect. A major advantage of the code talker system was its
speed. The method of using Morse code often took hours where
as, the Navajos handled a message in minutes. It has been said
that if was not for the Navajo Code Talker's, the Marines would
have never taken Iwo Jima.
• The Navajo's unwritten language was understood by fewer than
30 non-Navajo's at the time of WWII. The size and complexity
of the language made the code extremely difficult to
comprehend, much less decipher. It was not until 1968 that the
code became declassified by the US Government.
Navajo code talkers
• The Navajo Code Talkers, whose ranks exceed 400 during the
course of World War II in the Pacific Theater. Have been
credited with saving countless lives and hastening the end of the
war. The Code Talker's served in all six Marine divisions from
1942 to 1945.
• The Code Talker's primary job was to talk and transmit
information on tactics, troop movements, orders and other vital
battlefield information via telegraphs and radios in their native
dialect. A major advantage of the code talker system was its
speed. The method of using Morse code often took hours where
as, the Navajos handled a message in minutes. It has been said
that if was not for the Navajo Code Talker's, the Marines would
have never taken Iwo Jima.
• The Navajo's unwritten language was understood by fewer than
30 non-Navajo's at the time of WWII. The size and complexity
of the language made the code extremely difficult to
comprehend, much less decipher. It was not until 1968 that the
code became declassified by the US Government.
Descargar

CRYPTOGRAPHY - Brown University