NAVYA RAO

Presentation

by

CONTENTS

• DEFINITION

• CODES & CIPHERS

• HISTORY

• TYPES OF CRYPTOGRAPHY

• MODERN CRYPTOGRAPHY

• WHERE WE USE CRYPTOGRAPHY TECHNIQUES ?

• ADVANTAGES AND DISADVANTAGES

WHAT IS CRYPTOGRAPHY ?

CRYPTOGRAPHYGreek 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.

FNNC LNQMHMF

ANSWER :

GOOD MORNING

DO YOU UNDERSTAND

THIS ?

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

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 .

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.

PUBLIC KEYPublic 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.

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

VARIOUS KINDS OF CIPHERS

1) SUBSTITUTION CIPHERS

2) TRANSPOSITION CIPHERS

3) RAIL FENCE CIPHERS

4) ROUTE CIPHERS

SIMPLE CIPHERS (substitution ciphers)

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 .

German lorenz cipher machine used in world war

II to encrypt very high level general staff messages .

Military enigma machine invented by German

engineer Arthur at end of world war I .

TYPES OF CRYPTOGRAPHY

Symmetric key cryptogarphy

Quantum cryptography

Post Quantum cryptography

•Hash function cryptography

•Code based cryptography

Public key cryptography

Latice based cryptography

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

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

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

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

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

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