Cryptography
- 1. CRYPTOGRAPHY
- 2. INTRODUCTION CATEGORIES OF CRYPTOGRAPHY CRYPTOGRAPHIC FUNCTIONS BASIC TERMS ENCRYPTION & DECRYPTION SECURITY THREATS SECURITY GOALS APPLICATIONS CONCLUSION CONTENTS
- 3. Cryptography is the science and art of transforming messages to make them secure and immune to attack. It comes from Greek word "secret writing" WHAT IS CRYPTOGRAPHY
- 5. CATEGORIES OF CRYPTOGRAPHY ASYMMETRIC KEY CRYPTOGRAPHY SYMMETRIC KEY CRYPTOGRAPHY
- 6. • Symmetric-key cryptography started thousands of years ago when people needed to exchange secrets (for example, in a war). We still mainly use symmetric-key cryptography in our network security. Also known as secret key • In symmetric-key cryptography, the same key is used by the sender(for encryption) and the receiver (for decryption).The key is shared. SYMMETRIC KEY CRYPTOGRAPHY
- 7. • Also known as public key cryptography. • Sender & receiver uses different keys for encryption & decryption ASYMMETRIC KEY CRYPTOGRAPHY
- 8. • PLAIN TEXT • CIPHER TEXT • CIPHER • CRYPTOLOGY • KEY BASIC TERMS
- 9. SECRET KEY FUNCTIONS • Using a single key for encryption/decryption. • The plaintext and the cipher text having the same size. • Also called symmetric key cryptography PUBLIC KEY FUNCTIONS • Each individual has two keys – a private key (d): need not be reveal to anyone – a public key (e): preferably known to the entire world • Public key crypto is also called asymmetric crypto. HASH FUNCTIONS • A mathematical transformation that takes a message of arbitrary length and computes it a fixed-length (short) number. TYPES OF CRYPTOGRAPHIC FUNCTIONS
- 11. • A substitution technique is one in which the letters/number/symbols of plaintext are replaced by other letters/numbers/symbols. e.g. A D, T Z 2 5, 3 6 SUBSTITUTION CIPHERS TRANSPOSITION CIPHER • In the transposition technique the positions of letters/numbers/symbols in plaintext is changed with one another. • Plain text: MEET ME AFTER PARTY • Cipher text: TEMEEMEFAPTRYRAT • KEY USED: 421635 1 2 3 4 5 6 M E E T M E A F T E R P A R T Y 4 2 1 6 3 5 T E M E E M E F A P T R Y R A T
- 12. ENCRYPTION & DECRYPTION ENCRYPTION The process of converting plaintext into cipher text DECRYPTION The process of converting cipher text into plaintext ENCRYPTION & DECRYPTION
- 13. THREATS
- 15. • Defense services • Digital Signatures • Identification and Authentication • Internet payment systems • E- Commerce • Access control • Data security APPLICATIONS
- 16. By using of encryption techniques a fair unit of confidentiality, authentication, integrity, access control and availability of data is maintained. CONCLUSION