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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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