Concept of Cryptography Presented by KuralAmuthan.C.V Nirmalkumar.R.E Ramkumar.M Manimaran.M
What is cryptographyCryptography is the science of information security.The word is derived from the Greek, kryptos- hiddenGraphy-writing. It’s a efficient method of transmitting messages in asecured manner.
History of cryptography The history of cryptography has beenexplained in following slides with pictorialrepresentation It is further classified into• Ancient cryptography• Modern cryptography
Ancient cryptographySumerian’s cuneiform writing (3500 BC)
Ancient cryptographyEgypts cryptography writing(1900 BC)
Ancient CryptographyHistory tells us that Julius Caesar enciphered his dispatchesby 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 militaryduring world war I.
Modern cryptographyGerman Lorenz cipher machine, used in World War II toencrypt very-high-level general staff messages
Purpose of cryptographyAuthentication: The process of proving ones identity.Confidentiality: Ensuring that no one can read themessage except the intended receiver.Integrity: Assuring the receiver that the receivedmessage has not been altered in any way from the original.Non-repudiation: A mechanism to prove that thesender really sent this message
TerminologyKey word The shared secret used to keep the message secretCiphertext The encrypted messageEncryption The process of turning plaintext to ciphertextDecryption Opposite to the Encryption
Types of CryptographySymmetry cryptographyAsymmetry cryptographyHash function
Symmetric CryptographyUses same key for both encryption anddecryption
Asymmetric CryptographyAlso known as public keyUses two key (public & private) for encryptionand decryption Public key Private key
Hash functionHash function also called as message digestIt doesnt require the key, since plaintext notrecovered from ciphertext.Hash function are typically used forverification of file content.
Application of cryptography There are many applications available. Fewof them listed below.Digital SignatureSmart cardElectronic commerceComputer passwordATM
Conclusion Cryptography is only the part of securitysystem Its not a magic bullet Even though technology improved, there issome deflect. No one in world is perfect andstable we try improve our self in future needs