1) The document discusses the history of cryptography from ancient times to the 19th century. 2) It describes early encryption methods used by Greeks, Spartans, and Julius Caesar that involved transposition ciphers and substitution ciphers. 3) A major advance was the polyalphabetic cipher invented by Leon Battista Alberti in the 15th century, which used multiple cipher alphabets and was considered "unbreakable" at the time.

1. BSZQRPHSBQIZ
CRYPTOGRAPHY
Presented by Kinley

2. History of Cryptography
In the beginning: before 2000 BC
Before 2,000 BC
http://www.livius.org/a/turkey/mycale/mycale_map.gif 2

3. Around 1900 BC : In Egypt [Non-Standard
hieroglyphics]
http://www.bible-history.com/maps/maps/israel_and_her_neighbors.jpg 3

4. 487 BC: The Greek used a device called
the Scytale
http://flylib.com/books/2/827/1/html/2/images/1004.jpg
 Greeks and Spartans used this cipher to
communicate during military campaigns
 Called Transposition Cipher
4

5. 200–118 BC: Another Greek method was
developed by Polybius (now called the "Polybius
Square").
http://www.sciencephoto.com/image/363640/530wm/V4000161-Polybius_square-SPL.jpg
I AM A T T A C K E D
42 1123 23 44 44 11 31 52 51 41
I A M ATTACKED = 42 1123 23 44 44113152 5141
5

6. 60-50 BC: Caesar Shift Cipher
http://www.secretcodebreaker.com/ciphrdsk.gif
Encrypt (“BAD”, 3) = “EDG” Decrypt
(“EDG”, 3) = “BAD”
 Julius Caesar used it to communicate with his generals
during his military campaigns.
 It is also used to secure secret communications from
military leaders, diplomats, spies and religious groups
 Called Mono-alphabetic Substitution Ciphers
6

7. The Breaking Caesar Shift
Ciphers
 The algorithm was not particularly strong
 Using Frequency Analysis
In English (Source: Beker & VIDEO CLIP
Piper)
7

8. 15th Century: Leon Battista
Alberti
Leon Battista Alberti (1404–1472) was an
Italian author, artist, architect, poet, priest,
linguist, philosopher and general
Renaissance polymath. Being an
accomplished cryptographer, http://www.cs.trincoll.edu/~crypto/hi
He storical/alberti.jpg
published the earliest book on
cryptanalysis in western Europe,
created the first polyalphabetic cipher
(now known as the Alberti cipher)
invented the first encryption machine
(the Alberti Cipher Disk).
His polyalphabetic cipher was the most http://upload.wikimedia.org/wikipedi
a/commons/thumb/7/70/Alberti_ciphe
significant advance in cryptography since r_disk.JPG/250px-
Alberti_cipher_disk.JPG
Julius Caesar's time. 8

9. Encryption using single key in
Alberti Cipher Disk
 Its consisted of two metal
discs, one mobile, and one
immobile, attached by a
common axle so that the inner
disc may be rotated
Frequency Analysis:
The relative frequency of letters used in the English language. 'E' is
the most commonly used letter, followed by 'T', 'A', 'O' and 'I'
respectively.

10. Encryption using Multiple keys in Alberti
Cipher Disk
http://www.geocaching.com/seek/cache_details.aspx?guid=1b622946-92f8-4fad-a009-ce83b88791f2
 It was known as "unbreakable cipher” based on

11. 1790: Thomas Jefferson invented Wheel
cipher.
♦ America's minister to
France
♦ The wheel cipher consisted
of a row of cylindrical
wooden pieces, each
threaded onto an iron
spindle.
♦ The letters of the alphabet
were inscribed on the edge
of each wheel in a random
order.
Example:
♦ Turning these wheels,
http://www.cryptologicfoundation.org/content/A-Museum-Like-No-Other/images/m94_005.jpg
11

12. 19th Century: Blaise de Vigenère was a French
diplomat with Roman and cryptographer
• The Vigenère cipher is a method of
encrypting alphabetic text by using a
series of different Caesar ciphers
based on the letters of a keyword
• Vigenere’s polyalphabetic cipher
A B C D E F G H I
generalizes Caesar’s shift cipher and
J K L M N O P Q R S T U V W X Y Z
A
B
C
A
B
C
B
C
D
C
D
E
D
E
F
E
F
G
F
G
H
G
H
I
H
I
J
I
J
K
J
K
L
K
L
M
called
L
M
N
M
N
O
Vigenere
N
O
P
O
P
Q
P
Q
R
Q
R
S
polyalphabetic
R
S
T
S
T
U
T
U
V
U
V
W
V
W
X
W
X
Y
X
Y
Z
Y
Z
A
Z
A
B
Cipher
D D E F G H I J K L M N O P Q R S T U V W X Y Z A B C
E E F G H I J K L M N O P Q R S T U V W X Y Z A B C D
F F G H I J K L M N O P Q R S T U V W X Y Z A B C D E
G G H I J K L M N O P Q R S T U V W X Y Z A B C D E F
• Known as “The Unbreakable
H H I J K L M N O P Q R S T U V W X Y Z A B C D E F G
I I J K L M N O P Q R S T U V W X Y Z A B C D E F G H
J J K L M N O P Q R S T U V W X Y Z A B C D E F G H I
K K L M N O P Q R S T U V W X Y Z A B C D E F G H I J
Cipher” until Charles Babage
L L M N O P Q R S T U V W X Y Z A B C D E F G H I J K
M M N O P Q R S T U V W X Y Z A B C D E F G H I J K L
N N O P Q R S T U V W X Y Z A B C D E F G H I J K L M
O O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
P P Q R S T U V W X Y Z A B C D E F G H I J K L M N O
Q
R
S
Q
R
S
R
S
T
S
T
U
T
U
V
U
V
W
V
W
X
W
X
Y
X
Y
Z
Y
Z
A
Z
A
B
A
B
C
developed the Multiple frequency
B
C
D
C
D
E
D
E
F
E
F
G
F
G
H
G
H
I
H
I
J
I
J
K
J
K
L
K
L
M
L
M
N
M
N
O
N
O
P
O
P
Q
P
S
R
Analysis and Friedrich Kasiski,
T T U V W X Y Z A B C D E F G H I J K L M N O P Q R S
U U V W X Y Z A B C D E F G H I J K L M N O P Q R S T
V V W X Y Z A B C D E F G H I J K L M N O P Q R S T U
W W X Y Z A B C D E F G H I J K L M N O P Q R S T U V
X X Y Z A B C D E F G H I J K L M N O P Q R S T U V W
the Prussian military officer
Y Y Z A B C D E F G H I J K L M N O P Q R S T U V W X
Z Z A B C D E F G H I J K L M N O P Q R S T U V W X Y
http://www.ms-voynich.com/carrevig.gif
analyzes repetitions in the
Example: ciphertext to determine the exact
period and he is credited with 12

13. 1917 Century;
Gilbert Vernam was an engineer for
The American Telephone and Telegraph
Company.
He was asked in 1917, during WWI, to
develop a teletypewriter that encrypted
transatlantic telegraph messages sent by
the War Department to United States
troop commanders in Europe.
Vernam Cipher used a random key to
encrypt the message sent by telegraph
printer known as Vernam Cipher which
was the first example of online encryption.
The system, which was modified by the http://people.rit.edu/japnce/pay
ne/images/vernamcipherdevice1
Army Signal Corps, was later proved to be
.gif
unbreakable by using a different key every VIDEO CLIP
time a message was sent. This was called 13

14. Enigma
Machine
 Electro-mechanical cipher machine,
simple in design yet powerful in
capability
 Built in Germany in 1918 at the end
of WWI and later adapted for
 Uses rotors settings (the Germanencrypt
commercial use, and by key) to
each letter1926 message with a different
military in of a
cipher key
 Military added the plugboard to
commercial Enigma, greatly increasing
cryptologic strength
 Strength of Enigma design gave Germans
complete confidence in its security, even
http://math.arizona.edu/~dsl/images/enigma11.gif

15. 1932-1944:
♦The Pole, Marian Rejewski
attacked and broke the early
German Army Enigma system using
theoretical mathematics in 1932.
♦British code breakers designed
Bombe to decrypt Enigma cipher
machine Using Frequency analysis
designed by Alan Turing
♦It was the greatest breakthrough in
cryptanalysis in a thousand years
and more
http://math.arizona.edu/~dsl/images/enigma11.gif
15

16. Data Encryption
Standard (DES)
♦ 1972: U.S. Government recognized
the need to have a standardized
cipher for secret documents http://cryptodox.com/images/thumb/d/d5/Feistel.jpg/180px-Feistel.jpg
(encrypting classified and sensitive Horst Feistel was a German-born
cryptographer who worked on the
information) design of ciphers at IBM, initiating
research that would culminate in the
♦ NBS developed DES based on an development of the Data Encryption
Standard in the 1970s
earlier IBM algorithm, Horst Feistel's
Lucifer cipher.
♦ DES is a 64-bit block cipher algorithm
(64-bit block = 56-bit secret key +
8-bit parity) that uses a key of 56
bits and 16 rounds of
transposition and substitution to
Analysis of DES was the beginning of modern
cryptographic research of 8 (64-bit)
encrypt each group
plaintext letters.

17. Breaking of Data Encryption
Standard (DES)
 The key length of DES was too
short
• If a key is 56 bits long, that means there are
256 possible keys
• “DES Cracker” machines were designed to
simply brute force all possible keys
 1977: DES-cracking machine was used Diffie
and Hellman to find a DES key in a single day
 1993: Wiener used a key-search machine to find
a key within 7 hours http://www.eff.org/Privacy/Crypto
/Crypto_misc/DESCracker/
 DES was further weakened by the discovery of
differential cryptanalysis by Biham and Shamir in
1990 which requires 247 chosen plaintexts
• Ideally a ciphertext should be completely random, there
should be no connection to its matching plaintext
• Differential analysis exploits the fact that this is never actually the
case
• Uses patterns between plaintext and ciphertext to discover
the key
 There is evidence that IBM knew about differential

18. Advanced Encryption
 With DES effectively broken, a new standard was
Standard
needed
 U.S. Government made it an open
application/review process this time, and received http://www.boiledbeans.net/wp-
many submissions content/uploads/2008/06/7a813428ed
90cb02515fca28991a342c.jpg
 In 2001, after five years, Belgian cryptographers,
Joan Daeman and Vincent Rijman’s Rijndael
algorithm was selected by NIST become as the
 AES is a symmetricStandard (AES).
Advanced Encryption block cipher that can…
 Process data blocks of 128 bits.
 Uses cipher keys with lengths of 128, 192, and
256 bits.
 Variable number of rounds, each round 10, 12,
or 14 rounds depending on the key size
 The U.S. government approved AES for protecting
secret and top secret classified documents.
 This is the first time the United States has ever
approved use of a commercial algorithm derived
outside the government to encrypt classified data.

19. Current attacks against AES
 On AES with 128-bit keys, a brute force attack would
require 2128 work
 Any technique that can decrypt a ciphertext with less than 2 128
work is considered an attack
 Currently the best attacks on AES use variations of
differential cryptanalysis
 None of them could actually be completed before the sun burns
out
 None of them work on the full number of rounds
Video Clips

20. ♦ 1976: Whitfield Diffie & Martin Hellman published
New Directions in Cryptography.
♦ Develop the fundamental ideas of dual-key, or public key,
cryptography solving one of the fundamental problems of
cryptography, key distribution
♦ We use one key for encryption (the public key), and a
different key for decryption (the private key)
http://img.allvoices.com/thumbs/people
/135/135/44737066-whitfield-diffie.jpg
Video Clips

21.  1978: Ronald L. Rivest, Adi Shamir & Leonard
M.
Adleman (RSA) published RSA Algorithm for
Public Key System.
http://datanews.levif.be/ict/actualite/
 The RSA algorithm was publicly described in apercu/2011/02/17/un-lifetime-
achievement-award-pour-les-
1977 but was never deployed. It was not
pionniers-de-rsa/article-
1194952831693.htm
revealed until 1998 due to its top-secret
classification
 RSA was based on product of two large prime Video Clip
numbers
 Uses this product to create the public and Video Clip
private keys
 Sends the product and the public key one, who
can use them to encrypt messages
 Even if some one knows the product and the
public key, he/she can’t figure out the private
key unless he/ she can factor the product

22. Cryptography in Modern
Living
♦ Secure Communications
-Document / Data / Email
Encryption
♦ Identification and http://static.ddmcdn.com/gif/credit-card-3.jpg
Authentication
-Smart Cards
♦ Electronic Commerce and
Payments
–ATMs / Credit Cards
–Net Banking / Web Shopping

23. References
♦ Boone, J.V. (2005). A Brief History of Cryptology. Naval Institute Press, USA
♦ Damico,Tony M. (2009), A brief history of cryptography. Retrieved June 31, 2012,
http://www.studentpulse.com/articles/41/a-brief-history-of-cryptography
♦ Denning, Dorothy E. (1982). Cryptography and Data Security. Addison-Wesley Publishing
Company, Inc. Canada
♦ Macgregor, Mary. The Story of Greece [on-line]. Available: http://www.heritage-
history.com/www/heritage-books.php?
Dir=books&author=macgregor&book=greece&story=head
♦ Mackenzie, Dana (2003). The Code War. An article was provided by the National Academy of
Sciences. NW, Washington
♦ Pell, Oliver ().Cryptology. Retrieved July 18 2012, http://www.ridex.co.uk/cryptology
♦ Pfleeger, C.P & Pfleeger, S. L (2007). Security in Computing. Pearson education Inc. NJ,
USA
♦ Servos, William (2006). Cryptography. Retrieved July 18 2012,
http://www.cs.trincoll.edu/~crypto/historical/alberti.html
♦ Shannon, C. E. Communication Theory of Secrecy Systems. Retrieved 19 July 2012,
http://netlab.cs.ucla.edu/wiki/files/shannon1949.pdf
♦ Singh, Simon (1999). The Code Book. Doubleday, USA. pp. 279-92
♦ Wardlaw, W.P. The RSA Public key cryptosystem. Mathematics department, U.S naval
academy, Annapolis. Retrieved 19 July 2012,
http://www.usna.edu/Users/math/wdj/papers/cryptoday/wardlaw_rsa.pdf

24. Paremes Laosinchai, Ph.D

25. Example of Wheel Cipher Encryption
Plain Text: "The package is in the drop zone."
Rotate the individual disks until we spelled out that message as
shown.
Encrypted Message:
“EVAOSWMNDTKERXSKNKSEYFEEWS”

26. Example of Vigenère Cipher
♦ Plain Text:
ATTACKATDAWN
♦ Key: LEMON
♦ Plain text:
ATTACKATDAWN
♦ Key:
LEMONLEMONLE
♦ Cipher text:
♦ LXFOPVEFRNHR

27. 1930-1941:
In WWII, German military used Lorenz SZ
40 and SZ 42 cipher machines based on
Vernam cipher to encrypt tele-printer
messages.
To break the enormous amount of
encrypted message traffic the code breaker
had to build new, automated machines,
which lead directly to the development of the
first digital computers. http://blogs.guardian.co.uk/technology/Colossus_back
This was the first step in the evolution of _(800%20x%20600).jpg
1943-1944:
cryptography towards the new computer age.
British code breakers designed
Colossus Mark 1 and Colossus
Mark 2 to decrypt Lorenz cipher
machine using frequency analysis
Designed by Max Newman & Tommy
Flowers
27

28. What is Cryptography?
CRYPTOLOGY
Breaking of codes and cipher
Steganography
Cryptanalysis
(hidden) Code
(replace words)
Secret
Substitution
Writing
Cryptography
(scrambled) Cipher
(replace letters)
Transposition
28

29. Cryptographic Algorithm &
Operation