WHAT IS NETWORK
 A network is an interconnection
or a media between two or more
systems to share information
among them.
 The various threats caused to
network are :
 Remote Login
 Application Backdoors
 SMTP Session Hijackings
 Operating System Bugs
 Spams
 Viruses etc.

NETWORK SECURITY
 The security provided to the network
is called network security which at
present is looming on horizon as a
massive problem.
There are two kinds of Network
Security mainly as :
 Transit Security: It just encrypts
the packets to be transferred.
 Traffic Security : It acts just as a
screen between hosts & remote
sites.

OBJECTIVE OF SECURITY
 To avoid data threats
 To avoid denial of services
 To secure our data from masquerades
 To safeguard our data’s from traffic analyzer
 To not to make massage for the third person available

PASSWORD AUDITING
 Should not be in uppercase
 Must have at least 8 characters
 Must include alphabets, numeric keys & special
characters
 Password should not be the name of the user,
dictionary word etc.,
 It must be updated at least once a month

DATA SECURITY
 To monitor the user’s ACCESS
CONTROLS
 System that are connected in network must be protected
with firewalls
To protect the integrity & availability of the institution’s
information asset’s

PROBLEMS & ATTACKS
There are few intertwined areas in network security as:
 Secrecy
 Authentication
 Non-Repudiation
 Integrity Control etc.
The threats are classified into two categories :
Passive Attacks :
A passive attack is one in which the attacker eavesdrops and
listens to the message but can’t modify the message.
Active Attacks :
An active attack is one in which the attacker modifies, deletes,
replay or introduce new messages into the stream of message.

CRYPTOGRAPHY
 It is derived from the Greek word that meant for secret writing.
 Cryptography is a Software or Hardware programs
use Mathematical Functions , Formulas(Algorithms) to
change text from one form to another.
 Cryptography is the science and art of transforming messages to
make them secure and immune to attacks.
 It provides Confidentiality, Integrity, Accuracy.
 Applications of cryptography includes ATM cards, computer
passwords, and electronic commerce.
 It’s very useful to our Army & Police network to transfer
confidential data

TECHNIQUES
The data is transferred by applying two techniques
1.Encryption
2.Decryption
Encryption :The way of converting the plain text to the
cipher text by the means of few keys is called as the
“Encryption”.
Decryption :The way of converting the cipher text to
the plain text by the use of keys that are suitable to it is
called as “Decryption”.

SYMMETRIC KEY CRYPTOGRAPHY
 The implementation of a simple cryptography using
single key is done by the secret-key algorithms.
 Also known as SECRET KEY CRYPTOGRAPHY .
Sender & Receiver uses same key and an Encryption /
Decryption Algorithm to Encrypt / Decrypt data .
(i.e ) The Key is Shared
 This can be done by p-box, s-box and product cipher

SUBSTITUTION CIPHER
Replacing of each letter or
group of letters of plain text
into cipher text by another
letters is called as
“Substitution cipher”.
The substitution may be :
Monoalphabetic Substitution
Polyalphabetic Substitution

TRANSPOSITION CIPHER
 The change offered in
the position of the text
i.e. By jumbling the
words is called as
“Transposition cipher”.
 And the technique used
here is termed as “Mass
Technique”.

ASYMMETRIC KEY CRYPTOGRAPHY
 Also known as PUBLIC KEY CRYPTOGRAPHY . Sender &
Receiver uses different keys for Encryption & Decryption
namely PUBLIC & PRIVATE respectively
 Public key algorithms are formed when it satisfies the
following requirements:
o D(E(P))=P.
o Difficulty to deduce D from E.
o E cannot be broken by a chosen plain text attack.
D -> Deciphering E -> Enciphering

RSA ALGORITHM
 RSA is derived from the names of the 3 discoverers
named Rivest, Shamir, Adleman.
 The RSA algorithm is one of the widely used in the key
algorithms.
(1)The main function of this algorithm is providing
approach to public key cryptography & Encryption
(2) In this the CIPHER TEXT are the integer’s
between 0 to n-1
C =e M mod n m->message ,e->encryption
M=d C mod n C->cipher text ,d->decryption
=(e M) d mod n n-> integer’s (r*a) r & a are prime
=m e d mod n number’s

Symmetric key
cryptography
• Only 1 shared key is involved.
• The same key encrypts and
decrypts the plaintext.
• The shared key is kept secret
between Alice and Bob.
• Examples of Symmetric
algorithms:
– DES, 3DES, AES, IDEA,
BLOWFISH, TWOFISH, RC4,
RC5, SAFER etc.
Asymmetric key
cryptography
• Here 2 keys : a private and a
public key are involved.
• The Public key encrypts the
plaintext while the private key
decrypts it.
• The private key is just kept
secret by the Bob while the
public key is made public.
• Examples of Asymmetric
algorithms:
– Diffie-Hellman, RSA, El Gamal,
Elliptic Curve Cryptography
(ECC) etc.

APPLICATIONS
• Defense Services
• Secure Data Manipulation
• E – Commerce
• Business Transactions
• Internet Payment Systems
• User Identification Systems
• Access Control
• Data Security

PROPOSED CONCEPT
 As known the data has been easily hacked
even for the 52- bit encryption too. So, the
encryption bits of 52-bits should be given
with the combination of both numerals and
alphabets ( for example one alphabet is
placed for 13-bits each).
 The placement of alphabet is known only to
the particular sender & receiver such that it
secures the data to be sent.

CONLUSION
 This paper describes a technique to successfully
hiding and secure the data or massage with the
help of Encryption or Decryption technique with
the Cryptography And Network Security.
 However ,this research work & software package
provide a good starting point for anyone
interested in learning about Cryptography.

“For every lock there is a key………
It is better to keep safe your lock than the key”

Network security and cryptography

In this document