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‘In October 1586, in the forbidding hall of Fotheringhay Castle, Mary Queen of Scots was on trial for her life. Accused of treason and denied legal representation, she sat alone in the shadow of a vast and empty throne, belonging to her absent cousin and arch rival Elizabeth the I of England. Walsingham Elizabeth’s principle secretary had already arrested and executed Mary’s fellow conspirators. Her only hope lay in the code she used in all her letters concerning the plot. If her Cipher remains unbroken she might yet be saved. Not for the first time the life of an individual and the course of history depended on the arcane art of Cryptography.’ (To Decipher Title simply rotate the inner circle four letters to the right)
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cryptography 1

Mar 19, 2016

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Page 1: cryptography 1

‘In October 1586, in the forbidding hall of Fotheringhay Castle, Mary Queen of Scots was on trial for her life. Accused of treason and denied legal representation, she sat alone in the shadow of a vast and empty throne, belonging to her absent cousin and arch rival Elizabeth the I of England. Walsingham Elizabeth’s principle secretary had already arrested and executed Mary’s fellow conspirators. Her only hope lay in the code she used in all her letters concerning the plot. If her Cipher remains unbroken she might yet be saved. Not for the first time the life of an individual and the course of history depended on the arcane art of Cryptography.’

(To Decipher Title simply rotate the inner circle four letters to the right)

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M A R Y

Q U E E N

O F

S C O T S

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CONTENTS

Steganography ............................................................................... 1.

Cardarno......................................................................................... 7.

Caeser Cipher............................................................................. 11.

Arab Code breakers ................................................................... 13.

Mary Queen of Scots................................................................... 15.

Vigenere Cipher......................................................................... 19.

One Time Pad............................................................................. 21.

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1.

Before the inventions of cryptography people used steganography.

With Cryptography people hid the message by scrambling it up so nobody can read it. It’s right there staring you in the face but nobody knows what it means. With Steganography you hide the existence of the message.

Some examples of this include the Chinese writing a message on silk, wrap the silk in wax and swallow it. The guard would check the messenger but wouldn’t find anything. The Greeks would shave a slave’s head tattoo the message onto the head let the hair grow back then the slaves head would be shaved to reveal the

message. Another method would be to get a wax tablet scrap off the wax write the message then re-apply the wax to the message wouldn’t be visibleExtreme methods would be to kill the messenger like a disposable messenger system, so that the messenger wouldn’t go tell anybody else.

These techniques would also be used by The Babylon’s and Egyptians etc.The Chinese would now be the only ones to still use steganography as their character system is a lot more complicated where as the roman alphabet its a lot easier to use cryptography

Simon Singh 01.21

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5.

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10.

CARDANO CREATED A PIECE OF CARD WITH SMALL

HOLES CUT OUT. SO YOU WRITE OUT YOUR LETTER BUT

WHEN YOU PLACE THE CARD OVER IT YOU CAN ONLY

SEE MAYBE SEVEN OR EIGHT KEY LETTERS SPELLING

OUT A MESSAGE OF EXAMPLE THE LOCATION OF WHERE

AN ATTACK MIGHT HAPPEN. IT CAN ALSO BEEN SEEN

AS A FORM OF STEGANOGRAPHY. IT INVOLVES MAKING

THE CARD, CUTTING OUT THE HOLES, WRITE THE TEXT

MAKING SURE IT FITS, MAKE A COPY OF THAT CARD,

GET THE CARD TO THE OTHER

END SO THAT THEY CAN

DECODE IT. ITS HARD

WORK BUT ITS WORTH

IT IF YOU’VE GOT A

VALUABLE MESSAGE

Simon Singh 25.22

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11.

C R _ T O_ R A P H _

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When you have roman or conventional alphabet it’s easy to take the letters and jumble them around to make a kind of anagram, also know as transposition, or to substitute the letters for different letters or symbols. That is where the transition happens, from Steganography where you’re hiding the existence of the message to Cryptography where you’re hiding the meaning of

12.

the message by jumbling the letters or substituting them. Cryptography came around at the time when people started to write down information. People started to write down secrets. Whether it’s a personal diary, political, military, as soon as someone writing down their secret they need to find a way of hiding it.

Simon Singh 03.14

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13.

The Caesar Cipher came about around the time

of the Gallic wars. The first idea he had was to

just change the alphabet, instead if writing in

Roman letters just simply substitute

each Roman letter for a Greek

letter, send it in Greek

letters but with Roman

meaning and you’ve

got your secret

message. All you

need to decode

is to now what

happened. However

people were unaware

that this was happening.

Caesar used this during the Gallic

wars to raise a siege with Cicero. A Caesar shift

Cipher involves shifting the letters across so

many spaces for example shift

3 right would mean A would become D, B

would become E and C become F and so on

so by the end X would become A. So now

what you see is a coded message,

which is what you call a

cryptogram. This method

held for a long time

however with this

method you only

get 26 options. With

the substitution

cipher you get to

choose which letter is

substituted with which

so A could become Q and

B become T. so now instead of 26

keys you’ve got 400,000,000,000,000,000,00

0,000,000. This method held for 900 years.

(Fred Piper 05.22)

CAESAR CIPHER

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14.

I A I ZCTM, UMV EWZZG U W Z M IJWCB EPIB B P M G KIV’B AMM B P I V IJWCB

E P I B BPMG KIV.

‘RCTQCA KIMAIZ’SHIFT KEY 8

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21.

With the Vigenere there are 26 different keys you shift from 1,2,3,4 up to 26. You have a square, on each side of the square reads the letters A-Z then within that square you have 26 versions across and down of the alphabet, so you’ve got a square with multiple Letters inside. The first column would be B-A, second column C-B third column D-C and so on. So the first row would be the Caesar Cipher shift 1, second row Caesar Cipher shift 2 and Caesar Cipher shift 3 up to Caesar Cipher shift 25. Then you agree on a sequence of numbers let’s say 137, you use first row first and third row second and seventh row third. The amount of numbers you use is the number of Ciphers. By using this method it breaks the frequency analysis. Unfortunately the publication of the Vigenere Cipher was the Queen of Scots was executed.

VIGENERE CIPHER

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You can also use code words for example pen so you use the P Cipher, then E, then N. Again the complexity of your code will depend on the number of letters in the word. Say you have the word DOG with the Caesar Cipher and you shift it one space so D becomes E, O becomes P and G becomes H. If someone were to know that it was Caesar Cipher all you have to do is try 25 different shifts all you’ll get the message. With the Vigenere Cipher you have 26 cubed different ways. What you’re trying to do is break up the patterns. Language has rich patterns such as word lengths and vowel relationships, you’re trying to get from a very rich patterned message to something that looks completely random, has no pattern nor structure. Code breakers devour patterns and structure to get to the originalMessage, so you’re always trying to break up that pattern and that’s what a Vigenere Cipher does.

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15.

One way to solve an

encrypted message, if we

know its language, is to find

a different plaintext of the

same language long

enough to fill

one sheet

or

so, and then we count the

occurrences of each letter.

We call the most frequently

occurring letter the ‘first’, the

next most

occurring

letter the ‘second’ the following

most occurring letter the ‘third’,

and so on, until we account

for all the different letters in the

plaintext sample.

Then we look at the cipher text

we want to solve and we also

classify its symbols.

We find the most occurring

symbol and change it to the

form of the ‘first’ letter of the

plaintext sample, the next most

common symbol is changed

to the form of the ‘second’

letter, and the following most

common symbol is changed to

the form of the ‘third’ letter, and

so on, until we account for all

symbols of the cryptogram we

want to solve.

Lisa Jardine 09.12

(can you reveal the message opposite?)

FREQUENCY ANALYSIS

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16.

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Anthony Babington was a young

Catholic noble who joined a plot

to depose the Protestant Queen

Elizabeth I and put Mary Queen

of Scots on the English throne.

Sir Francis Walsingham, the

head of Elizabeth’s secret

service, captured a Catholic

plotter named Gilbert Gifford

and ‘convinced’ him to act as a

double agent. Gifford would act

as an intermediary smuggling

letters to Mary who was

imprisoned in Chartley Hall.

All the letters were given to

Walsingham. The letters were

written in a secret code called ‘a

nomenclator cipher’. Walsingham

had the code deciphered.

Walsingham waited and gathered

evidence that would implicate

Mary in a plot against Queen

Elizabeth.

On 28 June 1585 Babington

wrote to Mary outlining a plot

to murder Elizabeth and release

Mary with the support from an

invasion from Spain.

Myself with ten gentlemen and

a hundred of our followers will

undertake the delivery of your

royal person from the hands of

your enemies.

For the dispatch of the usurper,

from the obedience of whom we

are by the excommunication of

her made free, there be six noble

gentlemen, all my private friends,

who for the zeal they bear to

17.

MARY QUEEN OF SCOTS

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18.

the Catholic cause and your

Majesty’s service will undertake

that tragical execution.

Extract from Anthony Babington

letter to Mary, June 1585

Mary’s reply was intercepted

and sent to Walsingham. It

was sealed with a drawing of a

gallows. Walsingham had the

evidence he needed.

Babington and the other

plotters were arrested, tortured,

tried and condemned to be

hanged, drawn and quartered.

The damning evidence of the

letters between Mary and the

plotters was presented to Queen

Elizabeth. It was only a matter

of time before Mary would be

sentenced to death.

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The details are slightly murky because you’re never quite sure what really happened and what was set up for historians to later discover. One version of events is that Mary is communicating with plotters who are trying to release Mary from prison and assassinate Elizabeth and they use a code, because these are clearly treacherous attempts on the life of a queen. This code is not very different from

19.

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20.

the codes with which Al Kindi used the Frequency analysis. They used symbols and shapes for example they’re going to swap A for a diamond B for a square, c for a cross. They throw in some nice details, they throw in some red herrings, spurious characters which just pepper the Cipher which would confuse a potential code breaker they throw in a character that doubles the previous one

code breaker and despite all these little embroidery’s around the code you just count the letters, see which ones are most common and you break the code. There in front of you Elizabeth’s spymaster sees a letter, which proves undoubtedly that Mary is involved in a plot to assassinate Elizabethbethsimon sing 17.02

so if you’re doing bottle you put something after the tea to double the t. these message are sent to and fro where Mary replies back and says ‘yes lets go for it, I’m on board with this plot’. Unfortunately the person delivering this message is a double agent, Gifford, so whenever Gifford gets a message he takes it to Elizabeth’s spy master, Walsingham, who makes a duplicate and gives it to the

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ONE TIME PADThe One Time Pad is absolutely unbreakable, it’s guaranteed rock solid, if you encrypt a message with the One Time Pad and a I sent it to Fred and MI5 tapped our phone line they would never be able to break it. That’s why it’s so important, so wonderful. What you do is you write out you letter and take every single letter, for example you have a sequence of 100 letters and you’re going to shift every letter but every shift for each letter is going to be completely random. Before I encrypt the message, imagine you’ve got a 26 sided dice I roll the dice 100 times so i get a sequence of 100 random shifts, the first is going to maybe be shifted by ten places the second by four the third by eighteen and so on and because every shift is completely random the output is completely random and the code breaker has absolutely no patterns, almost the definition of random is something without any pattern or structure and that’s why you cannot break it.

Simon singh 31.34

23.

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However there are shortcomings. Let’s suppose you’re in Australia and I’m in England. I have used the One Time Pad method. I send you the cryptogram what can you do with it? Absolutely nothing until you know those random numbers I’ve added so you can take them off. So we’ve still got the problem of the messenger getting what you call the key, getting this random sequence to you. In certain scenarios that isn’t too difficult. The London Washington hotline is on that you can send in advance and you just tell them which one you’re using. So you will have say 1000 random sequences that you’ve sent earlier by very secure means. So the problem is the extra material you send to protect your messages is as much material as the message itself. The name One Time Pad gets its name because the code is used once then destroyed.

Fred Piper 32.42

That’s the beauty of the One Time Pad because as soon as you repeat anything in a cipher, you run the risk of being decoded. Repetition is the bugbear of any pattern; if you use the one time pad twice someone will notice. It’s very difficult for a person to generate randomness. The Enigma is a machine-enciphering machine developed for commercial use in the early 1920s and later adapted and appropriated by German and other Axis powers for military use through World War II. It electrically and mechanically generates multiple patterns of randomness but in ways that can be undone, reversed at the other end so if somebody has a machine at the other end, this machine has the capacity of reversing immediately all the complexity that you put in randomly when you encoded the message. The phrase use is ‘Sudo’ randomness.

Lisa Jardine 33.45

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