A short ppt on Cryptography . It contains just an abstract idea of Cryptography presented by Me for College Presentation .

2. NAVYA RAO
Presentation
by

3. CONTENTS
• DEFINITION
• CODES & CIPHERS
• HISTORY
• TYPES OF CRYPTOGRAPHY
• MODERN CRYPTOGRAPHY
• WHERE WE USE CRYPTOGRAPHY TECHNIQUES ?
• ADVANTAGES AND DISADVANTAGES

4. WHAT IS CRYPTOGRAPHY ?

5. CRYPTOGRAPHY
Greek word “crypto” meaning hidden or
secret, and “graphien” which means
“writing”.
Cryptology help us in performing secure
communications
through networks without allowing the
information dissemination to third
party.

6. FNNC LNQMHMF
ANSWER :
GOOD MORNING
DO YOU UNDERSTAND
THIS ?

7. K = J
L = K
M = L
N = M
O = N
P = O
Q = P
R = Q
A = Z
B = A
C = B
D = C
E = D
F = E
G = F
H = G
I = H
J = I
S = R
T = S
U = T
V = U
W =V
X = W
Y = X
Z = Y

9. CIPHER TEXT
The coded message is known as
Ciphertext. It depends upon the plaintext
and the secret key .
PLAIN TEXT
An original intelligible message or
data that is fed into the algorithm as
input .

10. The process of conversion of plaintext
into ciphertext is known as encryption.
The algorithm to encrypt data are called
as ciphers and the output they produced
is called ciphertext .
ENCRYPTION
DECRYPTION
Restoring the plaintext from cipher
text is known as decryption.

11. PUBLIC KEY
Public key is used to encrypt plaintext.
They are named as public keys because
they can be made public.
PRIVATE KEY
Secret keys are used to decrypt
ciphertext back to plaintext. They are
named as such because they are mean to
be private/secret.

13. Codes and Ciphers
 Ciphers are the way to scramble messages
so that people do not understand them modern
ciphers work with individual bits
 Codes usually work on larger chunks like words.
 While ciphers are mathematical algorithms
codes involve mapping from one language to
another,depend on code book ,code maker
 Cryptanalysis is not possible with encoded
messages since there is no math algorithm

14. VARIOUS KINDS OF CIPHERS
1) SUBSTITUTION CIPHERS
2) TRANSPOSITION CIPHERS
3) RAIL FENCE CIPHERS
4) ROUTE CIPHERS

15. SIMPLE CIPHERS (substitution ciphers)

16. HISTORY OF CRYPTOGRAPHY
Origin of cryptography 2000 B.C in Egypt
Trithemius German monk authored 6 books in 1518
on polygraphia and created a poly alphabetic cipher.
Nazi Germany used cryptography in World war I,II
Hitler used cryptography techniques to send
messages to his army
Mary queen of scots lost her life due to the coded
message which was being smuggled out of prison
being intercepted and decoded .

17. German lorenz cipher machine used in world war
II to encrypt very high level general staff messages .

18. Military enigma machine invented by German
engineer Arthur at end of world war I .

19. TYPES OF CRYPTOGRAPHY
Symmetric key cryptogarphy
Quantum cryptography
Post Quantum cryptography
•Hash function cryptography
•Code based cryptography
Public key cryptography
Latice based cryptography

20. MODERN CRYPTOGRAPHY
• Shannon was the front runner of modern
cryptography based on mathematics used by
government organisations like NSA .
• In 1970 Data Encryption System (DES) brought by
IBM now being replaced by AES (advanced
encryption system) .
• Recently a public key called Defi Hellman key
introduced new method of key distribution and
New class of coding algorthm
• Private and public keys diminished the reqt of
secure channels

21. DES
• Block cipher which work by running an operation
for 16 rounds on block of 64 bits
• On each round it takes the second half of the
plaintext (32 bits) and transform it into different
texts using a pre designed algorithm (RSA – Ron
Rivest Adi Shamir Leonared Adlman)
• It does a XOR operation of the result with the first
half of the palintext
• The result is prosessed by algorithm in the next step
while the second half is XOR with the result of the
first

22. WHERE DOES CRYPTOGRAPHY
TECHNIQUES USED ?
 Military agencies
 Industries
 Internet banking
 Bussiness deals
 Electronic money
 Computer passwords
 Network communication
 Private confidential matters
 Facebook,Gmail
 HTTPS site

23. ADVANTAGES
• It hides the message and your privacy is safe such as
financial reports,employee data,medical records,etc.
(Seceracy & integrity in transmission & storage)
• No one would be able to know what it says unless
there’s a key to code (authentication of identity)
• You can write whatever you want and how ever you
want to keep your code a secret.
• More secure than stegnography
• Does not need any additional carrier
• Used to scramble satellite signals

24. ADVANTAGES
• Credentialing systems (proving the
competance)
• Digital signatures (mechanism by which
message is authenticated)
• Electronic money transfer,electronic fund
transfer (EFT)
• Threshold crypto system (require minimum
number of parties to decrypt)
• Secure multi-party computation

25. DISADVANTAGES
• It takes long time to figure out the code
• It takes long to create the code
• If you were to send a code to another
person in the past , it will take long to get
to that person
• Overall cryptography is a long process