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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: ( )CRYPTOGRAPHY contd
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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: ( )CRYPTOGRAPHY contd
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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