PAPER PRESENTATION ON

CRYPTOLOGY

BY:-K.Srinivas

CRYPTOLOGY

Cryptology Also called as cryptography From Greek κρυπτός, kryptos, "hidden,

secret" Is the practice and study of hiding

information

TERMINOLOGY

Encryption

Decryption

Cipher and

Keys

HISTORY OF CRYPTOGRAPHY

The Ancient Greek scytale, probably much

like this modern reconstruction, may have

been one of the earliest devices used to

implement a cipher

TYPES OF CIPHER

Classical ciphers

Substitution ciphers

Polyalphabetic ciphers

EXAMPLES FOR CIPHERS

In Classical cipher type -

“help me” becomes “ehpl em”

In Substitution cipher type -“fly at once”

becomes “gmz bu podf”

POLYALPHABETIC CIPHERS

The Polyalphabetic ciphers were developed

by Leon Battista Alberti around the year

1467.

CREDIT CARD WITH SMART CARD

MODERN CRYPTOGRAPHY

Symmetric-Key cryptography

Public-Key cryptography

Cryptanalysis

Cryptographic primitives

SYMMETRIC-KEY CRYPTOGRAPHY

Block cipher

Example: AES and DES

Stream cipher

Example: RC4

PUBLIC-KEY CRYPTOGRAPHY

PUBLIC-KEY CRYPTOGRAPHY

Public-Key is also called as “Asymmetric-

key”

The Public-Key is used for encryption and

the Private-Key is used for decryption

DIGITAL SIGNATURE

A digital signature is an reminiscent of an

ordinary signature. It uses two algorithms

1. Signing

2. Verification

PADLOCK ICON

CRYPTANALYSIS

The goal of cryptanalysis is to find some

weakness or insecurity in a cryptographic

scheme, thus permitting its subversion or

evasion

CRYPTANALYTICAL ATTACKS Cipher text-only attack

Known-plaintext attack

Chosen-plain text

CRYPTOSYSTEMS

Cryptographic primitives provide

fundamental properties, which are used to

develop more complex tools called

cryptosystems or cryptographic protocols

APPLICATIONS

Security of ATM cards

Computer passwords

Electronic commerce

QUESTIONS

THANK YOU