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[ WINTER, 2015 ] ASSIGNMENT
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PROGRAM
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MCA(REVISED FALL 2012)
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SEMESTER
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V
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SUBJECT CODE & NAME
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MCA5042- Cryptography and Network
Security
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CREDIT
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4
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BK ID
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B2069
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MAX. MARKS
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60
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Answer all the Questions
Question.1. Define computer security.
Explain the important objectives of computer security.
Answer:Computer security, also known as cybersecurity or IT security, is the
protection of information systems from theft or damage to the hardware, the
software, and to the information on them, as well as from disruption or
misdirection of the services they provide. It includes controlling physical
access to the hardware, as well as protecting against harm that may come via
network access, data and code injection,and due to malpractice by operators,
whether intentional, accidental, or due to them being tricked into deviating
from secure procedures.
The field is of growing importance due to the
Question.2. Explain Feistel Cipher.
Answer:In cryptography, a Feistel cipher is a symmetric structure used in the
construction of block ciphers, named after the German-born physicist and
cryptographer Horst Feistel who did pioneering research while working for IBM
(USA); it is also commonly known as a Feistel network. A large proportion of
block ciphers use the scheme, including the Data Encryption Standard (DES). The
Feistel structure has the advantage that encryption and decryption operations
are very similar, even identical in some cases, requiring only a reversal of the
key schedule. Therefore the size of the code or circuitry required to implement
such a
Question.3. Explain the following.
(a) Asymmetric Keys
Answer:An asymmetric algorithm, as outlined in the Diffie-Hellman paper, is a
trap door or one-way function. Such a function is easy to perform in one
direction, but difficult or impossible to reverse. For example, it is easy to
compute the product of two given numbers, but it is computationally much harder
to find the two factors given only their product. Given both the product and
one of the
(b) Public Key Certificate
Answer:Asymmetric cryptography or public-key cryptography is cryptography in
which a pair of keys is used to encrypt and decrypt a message so that it
arrives securely. Initially, a network user receives a public and private key
pair from a certificate authority. Any other user who wants to send an
encrypted
(c) Public Key (Asymmetric) Cryptographic
Algorithm
Answer:Public-key cryptography refers to a set of cryptographic algorithms that
are based on mathematical problems that currently admit no efficient solution
-- particularly those inherent in certain integer factorization, discrete
logarithm, and elliptic curve relationships. It is computationally easy for a
user to
(d) Public Key Infrastructure (PKI)
Answer:A public key infrastructure (PKI) is a set of hardware, software, people,
policies, and procedures needed to create, manage, distribute, use, store, and
revoke digital certificates and manage
Question.4. (a) Explain digital signature.
Answer: A digital signature is a mathematical scheme for demonstrating the
authenticity of a digital message or documents. A valid digital signature gives
a recipient reason to believe that the message was created by a known sender,
that the sender cannot deny having sent the message (authentication and
non-repudiation), and that the message was not altered in transit (integrity).
Digital signatures are commonly used for software distribution, financial
transactions, and in other cases where it is important to detect forgery or
tampering.
(b) Explain the different types of attacks
on digital signatures.
Answer:In their foundational paper, Goldwasser, Micali, and Rivest lay out a
hierarchy of attack models against digital signatures:
·
In a
key-only attack, the attacker is only given the public verification key.
·
In a
known message attack, the attacker is given valid signatures for a variety of
messages known by the attacker but not chosen by the attacker.
·
In an
adaptive chosen
Question.5. Explain the Benefits of IP security.
Answer:Internet Protocol Security (IPSec) is a framework of open standards for
ensuring private, secure communications over Internet Protocol (IP) networks,
through the use of cryptographic security services. IPSec is a suite of
cryptography-based protection services and security protocols. Because it
requires no changes to programs or protocols, you can easily deploy IPSec for
existing networks.
The driving force for the acceptance and
deployment of secure IP is the need for business and government users to
connect their
Question.6. Define the following terms used
in the IEEE 802.11 standard.
(a) Access point (AP)
Answer:In computer networking, a
wireless access point (WAP) is a networking hardware device that
allows wireless devices to connect to a wired network using Wi-Fi, or related
standards. The AP usually connects to a router (via a wired network) as a
standalone device, but it can also be an integral component of the router
itself. An AP is differentiated from a hotspot, which is the physical space
where
(b) Basic
service set (BSS)
Answer: Basic Service Set is a component of the IEEE
802.11 WLAN architecture. This network architecture is built around a Basic
Service Set (BSS), which is actually a set of STAs (the component that connects
to the wireless medium such as a network adapter or NIC) that communicate with
each other. When one access
(c)
Coordination function
Answer:Distributed coordination function (DCF) is
the fundamental MAC technique of the IEEE 802.11 based WLAN standard. DCF
employs a CSMA/CA with binary exponential backoff algorithm.
DCF
(d)
Distribution system (DS)
Answer:A wireless distribution system (WDS) is a
system enabling the wireless interconnection of access points in an IEEE 802.11
network. It allows a wireless network to be expanded using multiple access
points
(e)
Extended service set (ESS)
Answer:An extended service set (ESS) is one or more
interconnected basic service sets (BSSs) and their associated
Dear students get fully solved
assignments
Send your semester &
Specialization name to our mail id :
“ help.mbaassignments@gmail.com ”
or
Call us at : 08263069601