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COMPUTER

APPLICATIONS INBUSINESS

PRESENTATION ON -

CRYPTOGRAPHY

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INTRODUCTION

Cryptography is a field of science involved with the encryption

and decryption of data such that when a data is encrypted with

a password, it is rendered unreadable or completely unusable

until it is decrypted by either the same password or another of

a suitable nature.

It would be preferable that the password for decryption be held

only by the intended viewers such that the encrypted data

becomes completely secure and is only accessible to those

who are supposed to access it.

Without the correct password for decryption, a hijacker is

unable to use the encrypted data in any way whatsoever unlesshe manages to crack the algorithm used to encrypt the data.

Strong algorithms will require hundreds or thousands of years

with current hardware to crack while the weakest ones take

average hardware slightly over a few seconds to break.2


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HISTORY OF CRYPTOGRAPHY

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Julius Caesar (who was

believed to pioneer

cryptography) invented a

code language called the

Caesar cipher. It was an

easily broken code, but in atime where cryptography

was unheard of, it became a

major factor in him winning

his wars.

The Caesar cipher worked

simply by shifting the letters

in the alphabet by an

arbitrary number of

positions by the setter of the

code.


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Symmetric Cryptography It

is the kind of cryptography

where one password is used

to both encrypt and decrypt a

message or any other forms ofdata.

Asymmetric Cryptography -

Commonly called public key

cryptography, it involves a

public key, which is used to

encrypt the message, and aseparate private key, which is

used to decrypt the message.

This being an information age,

the amount of data that we

deal with everyday is a

frighteningly huge amount.

Some of the data that wetransmit over communication

channels are meant only for

the receiver to read and view

but as these channels are

open to the public, there is no

stopping it from beingaccessed by anybody who

wants to see it for whatever

ulterior motive they may have.

TYPES OF

CRYPTOGRAPHY

CRYPTOGRAPHY

AND YOU


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ENCRYPTION &

DECRYPTION

WHAT IS

CRYPTO-GRAPHY

STRONG

CRYPTO-GRAPHY

HOW

DOESCRYPTO-

GRAPHY

WORK?


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CONVENTIONAL

CRYPTOGRAPHY

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CAESARS

CIPHER

KEY

MANAGEMENT

&CONVENTION-

AL

ENCRYPTION


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PUBLIC KEY

CRYPTOGRAPHY

HOW PGP

WORKS?


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KEYS

A key is a value that works with a cryptographic algorithm to

produce a specific cipher text.

Public key size and conventional cryptography's secret key size

are totally unrelated.

While the public and private keys are mathematically related,it's very difficult to derive the private key given only the public

key; however, deriving the private key is always possible given

enough time and computing power.

Larger keys will be cryptographically secure for a longer period

of time.

Keys are stored in encrypted form. PGP stores the keys in twofiles on your hard disk; one for public keys and one for private

keys. These files are called keyrings.

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DIGITAL SIGNATURES

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SIMPLE SECURE


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DIGITALCERTIFICATES

CERTIFICATEDISTRI-BUTION

CERTIFICATESERVERS

PUBLIC KEYINFRASTRUC

-TURES

CERTIFICATEFORMATS

PGPCERTIFICATE

X.509CERTIFICATE

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PGP CERTIFICATE FORMAT

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The PGP version

number

The certificate

holders public

key

The certificate

holdersinformation

The digital

signature of the

certificate owner

The certificates

validity period

The preferred

symmetric

encryption

algorithm for the

key


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X.509 CERTIFICATE FORMAT

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The X.509 version

number

The certificate

holders public key

The serial number of

the certificate

The certificateholders unique

identifier

The certificates

validity period

The unique name of

the certificate issuer

The digital signature

of the issuer

The signature

algorithm identifier


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VALIDITY& TRUST

CHECKINGVALIDITY

ESTABLISH-ING TRUST

META &TRUSTED

INTRODU-CERS

TRUSTMODELS

DIRECT

TRUST

HIERAR-CHIALTRUST

WEB OF

TRUST

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CERTIFICATE

REVOCATION

KEY SPLITTING

WHAT IS A

PASSPHRASE?


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CONCLUSION

Cryptography is emerging as a very important tool in the field

of security today.

With security becoming a very important field in the world of

today, cryptography is being catapulted into the limelight

together with other methods of security. Indeed cryptography

is one of the first lines of defense against hackers and crackers

in todays world.

Thus, it will stay important for a long time to come as it has for

thousands of years since Caesar first invented the Caesar

cipher in an era before the birth of Christ.

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GROUP

MEMBERSAND

THEIR

ROLLN

UMBERS

SHREEKANT

BADRI 162

RIDDHISH

BHAYANI 163

FARHAN

CHUNAWALA

164

YASH DAMANI

165

NORTON DAVID

166

SAHIL DHAMI -

167

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