CRYPTOGRAPHY AND ENCRYPTION

Ancy mariam babuVit university

INTRODUCTION the need of multimedia secure

transmission need of more security What is cryptography…???

CRYPTOGRAPHY CRYPTOGRAPHY IS THE

SCIENCE OF INFORMATION SECURITY

The word is derived from greek kryptos means hidden

Cryptography includes the techniques such as microdotes, merging words with images, other ways to hide information in storage or transit

Objectives of cryptography are

confidentiality

integrity

authentication

COMPONENTS OF CRYPTOGRAPHY

Encryption : it is the process of converting a plain text into (unrecognizable) cipher text.

For strong encryption: two attributes -confusion -diffussion Decryption: it is the process of changing

back the cipher text to plain text.

COMPONENTS OF CRYPTOGRAPHY

CATEGORIES OF CRYPTOGRAPHY

SYMMETRIC KEY CRYPTOGRAPHY

A single common key is used for encode and decode of messages

Both sender and receiver must know the common key

The common key need to be exchange before hand by some other secure method

Symmetric key encryption is fast and simple But the key management is impractical

SYMMETRIC KEY CRYPTOGRAPHY

ASSYMETRIC KEY CRYPTOGRAPHY

Two different key is used for encryption and decryption

Public key is used for encryption and private key is used for decryption

Each user has a public key and corresponding private key.

ASSYMETRIC KEY CRYPTOGRAPHY

ENCRYPTION… Encryption is the

process of converting plain text into cipher text.

Done by using encryption algorithms

Key is used Two types:

-Asymmetric

-symmetric

ASYMMETRIC ENCRYPTION

SYMMETRIC ENCRYPTION

WHY USE ENCRYPTION Authentication

-protects personal data such as passwords Privacy

-provides for confidentiality of private information

Integraty

-ensures that a document or file not has been altered.

Accountability

- prevents denial or plagarism

EXAMPLES OF ENCRYPTION

Web browser encryption Email encryption Hard drive encryption Operating system protection

VIDEO ENCRYPTION Encryption on video Twotypes

- independent encryption

-joint compression and encryption

INDEPENDENT ENCRYPTION

Both encryption and compression done seperatly

Any compression standard can use for compression

For encryption, can use either lightweight encription or heavyweight encryption

INDEPENDENT ENCRYPTION

HEAVY WEIGHT ENCRYPTION

Video encryption technique

Huge computation overhead

More secure

HEAVYWEIGHT ENCRYPTION TECHNIQUES Examples Des:

- data encryption standard for electronic encryption

-short key length and symmetric key block cipher

Aes:

-advanced encryption algorithm

- symmetric key encryption Rsa:

-public key scheme

- difficulty for factoring large number

-secure

LIGHTWEIGHT ENCRYPTION

Video encryption technique

Faster and simple Less complexity Less time cosumption

LIGHTWEIGHT ENCRYPTION TECHNIQUES examples Rc6 Idea hb2 Present Tea

JOINT COMPRESSION AND ENCRYPTION TECHNIQUE

Both encryption and compression integrates as a single step

System obtain multiple level of security Exaples

1.vea

2.rvea Two types

1.compression before encryption

2. compression after encryption

COMPRESSION BEFORE ENCRYPTION

COMPRESSION AFTER ENCRYPTION