Cryptography

Concept of Cryptography

Presented by

KuralAmuthan.C.VNirmalkumar.R.E

Ramkumar.MManimaran.M

What is cryptography

Cryptography is the science of information security.

The word is derived from the Greek, kryptos- hidden Graphy-writing.

It’s a efficient method of transmitting messages in a secured manner.

History of cryptography

The history of cryptography has been explained in following slides with pictorial representation

It is further classified into • Ancient cryptography• Modern cryptography

Ancient cryptography

Sumerian’s cuneiform writing (3500 BC)

Egypt's cryptography writing(1900 BC)

Ancient cryptography

Ancient Cryptography

History tells us that Julius Caesar enciphered his dispatches by writing D for A Ex: If message is “CALL ME” means, It is encrypted to“FDOO PH“

Modern cryptography

“The Enigma Machine” invented by German military during world war I.

Modern cryptography

German Lorenz cipher machine, used in World War II to encrypt very-high-level general staff messages

Purpose of cryptography Authentication: The process of proving one's identity.

Confidentiality: Ensuring that no one can read the

message except the intended receiver.

Integrity: Assuring the receiver that the received

message has not been altered in any way from the original.

Non-repudiation: A mechanism to prove that the

sender really sent this message

Outline of Cryptography

Terminology

Key word The shared secret used to keep the message secret

Ciphertext The encrypted message

Encryption The process of turning plaintext to ciphertext

Decryption Opposite to the Encryption

Types of Cryptography

Symmetry cryptography

Asymmetry cryptography

Hash function

Symmetric Cryptography

Uses same key for both encryption and decryption

Asymmetric Cryptography

Also known as public key Uses two key (public & private) for encryption and decryption

Public key Private key

Hash function

Hash function also called as message digest

It doesn't require the key, since plaintext not

recovered from ciphertext.

Hash function are typically used for

verification of file content.

Application of cryptography

There are many applications available. Few of them listed below.Digital Signature Smart card Electronic commerce Computer password ATM

Conclusion

Cryptography is only the part of security system Its not a magic bullet Even though technology improved, there is some deflect. No one in world is perfect and stable we try improve our self in future needs

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