Network Security & Cryptography m.susmitha ( i.t )

8/9/2019 Network Security & Cryptography m.susmitha ( i.t )

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S A G E O F C R Y P T O G R A P H Y I NE T W O R K S E C U R I T YBYM.SUSMITHA ( I.T )

WELCOMEELCOMEEMINAR ONEMINAR ON


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:BSTRACT

v Security has become a more sensible issue in REALWORLD or CYBER WORLD.

v It is a complicated subject which is deal by well-trainedand experienced experts.v The security mechanisms are primarily based on

cryptographic algorithms.v The main purpose of the algorithms are to achieve

optimal speed and security levels.

vv


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:CONTENTS

qIntroductionqPopular networksqSecurity servicesqSecurity threats/ AttacksqFire wallsqSecurity mechanisms

qCryptographyqTypes of cryptographyqConclusion


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:INTRODUCTION

The main purpose of computernetworks is to understand theprinciples of network security.

Users want to exchange the data in asecure way.

The problem of network issue is a

complex issue.Network security means a protection

of the network assets.


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:POPULAR NETWORKS

UUCP:Unix to Unix Copy It was developed to connect

UNIX hosts together.

INTERNET: It is the worlds largestnetwork of networks.


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:SERVICES FOR SECURITY

1.CONFIDENTIALITY: Ensure thatinformation in a computer systemand transmitted information are

accessible only read by authorizedparties.

2.AUTHENTICATION: Ensure that the origin

of message is correct.3.INTEGRITY: Ensure that only authorizedparties are able to modify computersystems or transmitted information.


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SERVICES FOR SECURITY:( contd )

4. NON-REPUDIATION: Requires thatneither sender nor receiver of amessage is able to deny the

transmission.5. ACCESS CONTROL: Requires that

access to information resources may

be controlled for target system.6. AVAILABILITY: The availability of

computer systems must be only forauthorized parties when ever needed.


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:ATTACKS


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: ( )ATTACKS contd

PASSIVE ATTACKS: the goal of attacker is toobtain the information that is beingtransmitted.

ACTIVE ATTACKS: it involve somemodification of the data stream or thecreation of false data stream.

DENIAL OF SERVICE: ->Not running your visible-to-the-

world servers at a level too close tocapacity ->Using packet filtering to prevent

obviously forged packets from entering intoyour network address space.

->Keeping up-to-date on security-related atches for our hosts' o eratin


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:( )ATTACKS contd

UNAUTHORIZED ACCESS: The goal ofthese attacks is to access someresource that your machine should not

provide the attacker. These can takethe form of a virus, worm, or Trojanhorse. One of the most publicizedthreats to security is intruder orhacker or cracker.

WHERE DO ATTACKS COMEFROM?:Through any connection that

you have to the outside world. This

includes Internet connections, dial-upmodems and even h sical access.


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:( )ATTACKS contd

PREVENTING SECURITY DISASTERS: 1. hope your computer have

backups. 2. dont put data where it doesnt

need to be 3. avoid systems with single points

of failure 4. watch for relevant security

advisories.


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:FIRE WALLS

o Firewalls can be an effective meansof protecting a local system ornetwork of systems from network

based security threats while at thesame time, a firewall is simply agroup of components that

collectively form a barrier betweentwo networks.

oTYPES OF FIRE WALLS: 1. Application gate ways 2. Packet filterin


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: ( )FIRE WALLS contd

o POINTS OF FAILURE: Any time thereis only one component payingattention to what's going on

between the internal and externalnetworks, an attacker has only onething to break (or fool!) in order to

gain complete access to yourinternal networks.


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:SECURITY MECHANISMS

vA mechanism that is designed todetect, prevent, or recover from asecurity attack. Cryptography and

Steganographic are such twotechniques. Hence we focus ondevelopment, use and management

of Cryptographic techniques.


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:CRYPTOGRAPHY

the word cryptography is derivedfrom Greek means secret writing.

the process of encoding and decodingthe data is called cryptography.

encryption refers to thetransformation of data from plain

text to cipher text.decryption refers to the

transformation of cipher text to

original data.


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: ( )CRYPTOGRAPHY contd

ciphers are broken into 2 categories. 1. substitution ciphers

2. transposition ciphersSubstitution ciphers replace letters inthe plaintext with other letters orsymbols, keeping the order in which

the symbols fall the same.Transposition ciphers keep all of the

original letters intact, but mix up

their order.


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Substitution cipher: Plaintext letter

A B C D E F G H Cipher text letter F H E A C D G B


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:TYPES OF CRYPTOGRAPHY

There are 3 types of cryptographicalgorithms. They are

1. secret key algorithm 2. public key algorithm 3. hash algorithms


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:SECRET KEY CRYPTOGRAPHY

vit involves the use of single key.vit is also known as symmetric

cryptography. Encryption Plain text ------------------> cipher text Key Cipher text------------------> plain text Decryption


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:SECRET KEY CRYPTOGRAPHY( )contd

ADVANTAGES: 1.widely used and very popular.

2. very fast relative to public keycryptography. 3.cipher text is compact.

DISADVANTAGES: 1. administration of keys become

extremely complicated. 2. key is subject to interception by

hackers.


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:PUBLIC KEY CRYPTOGRAPHY

it is also known as asymmetriccryptography.

it is used to provide privacy orconfidentiality.

Encryption Plain text

---------------------------------> cipher text Public key

Private key


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:HASH ALGORITHMS

it is also known as one waytransformations.

it is a mathematical transformationthat takes a message of arbitrarylength and computes from it a fixedlength number.

PASSWORD HASHING:When a usertypes a password, the system muststore the password encryptedbecause someone else can use it.

To avoid this problem hashing is


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: ( )HASH ALGORITHMS contd

MESSAGE INTEGRITY:Cryptographichash functions can be used toprotect the integrity of a message

transmitted over insecure media. MESSAGE FINGERPRINT: We can

know whether some data stored has

been modified from one day to thenext, if we save that data structurewith a hash function.


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: ( )HASH ALGORITHMS contd

DIGITAL SIGNATURES:can beefficiently implemented using hashfunctions.

KEY SIZE:This has major role foramount of security. If the algorithmis inherently strong, then it can be

assumed that the larger the keysize for the ciphers, the harder it isfor a hacker to perform an attack onthe cipher text.

HYBRID SYSTEMS: Just one crypto-


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:CONCLUSION

Everyone has a differentidea of what ``security'' is, and whatlevels of risk are acceptable. when

new security methods are developed,breaking of these methods hasincreased. Cryptography is evergreen

and developments in this area are abetter option.


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QUERIES

QUERIES?


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THAN

K YOUTHAN

K YOU

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Network Security & Cryptography m.susmitha ( i.t )