Sunanda cryptography ppt

SRINIVASA INSTITUITE OF
TECHNOLOGY & SCIENCE

CRYPTOGRAPHY & NETWORK
SECURITY
Presented By
S.Sunanda

Contents
•Cryptography
Techniques
Encryption & Decryption
Categories Of Cryptography
Traditional ciphers
RSA algorithm
Applications

Contd…..
• Network Security
What is Network?
 About Network Security
Security Goals
Objective Of Security
Data Security
Problems & Attacks
Threats
Conclusion

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 from 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 .
 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 letter or group of letters of
plain text into cipher text
by another letter is called
as “Substitution cipher”.
The substitution may be:
Monalphabetic 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.

RSA ALGORITHM
RSA is derived from the names of the
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 and n-1

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

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
* 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 message 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.
THREATS

CONCLUSION
 However, through this Cryptography &
Network Security We Successfully
hiding and secure the data with the help
of Encryption & Decryption.

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

Sunanda cryptography ppt

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