CONTENTS

SECURITY SECURITY THREATSSECURITY GOALSWHAT IS CRYPTOGRAPHYBASIC TERMSENCRYPTION & DECRYPTIONCATEGORIES OF CRYPTOGRAPHYCOMPARISONCONCLUSION

WHAT DOES SECURITY MEAN?

SECURITY???Network security is an over arching term.

Security threats

1. Passive threats2. Active threats

PLAIN TEXT CIPHER TEXT CIPHER ENCRIPTION & DECRYPTION KEYS

BASIC TERMS

CATAGORIES OF CRYPTOGRAPHY

A. Symmetric cryptographyB. Asymmetric cryptography

SYMMETRIC KEY CRYPTOGRAPHYo also known as secret key cryptography.o Sender & receiver uses same key for

encryption & decryption namely public key

a. Traditional cipher b. Modern cipherTwo types traditional cipheri. Substitution cipherii. Transposition cipher

Types of ciphers

Substitution cipher

A substitutional cipher is one in which the letters/numbers/symbols is replaced by other letters/numbers/symbolse.gA d, t z

2 5, 3 6

Asymmetric key cryptography Also known as public key Sender and receiver uses different keys for encryption and decryption namely public & private key

COMPARISON

Symmetric key cryptography

Asymmetric key cryptography

1. The same algorithm with same key is used for encryption & decryption

2. The key must be kept secret

3. may be impossible or at least impractical to decipher a message if no other information is given

1. One algorithm is used for encryption & other for decryption with a pair of keys respectively

2. One of the key must be kept secret

3. It may be impossible or at least impractical to decipher a message if no other information is given

applications

• Defense services• Secure data manipulation• Business transactions• Internet payment systems• User identification systems• Acess control• Data security

conclusion

By using of encryption techniques ,a fair unit of confidentiality,authentication,integrity,acess control and availability of data is maintained

thanks