Computer Security - Computer Science - Grade X - New Syllabus
Computer Security / Cyber Security
— The
protection of computer systems and information from harm, theft, and
unauthorized use.
— Proper
computer security helps prevent viruses and malware, which allows programs to
run quicker and smoother.
Tips for Best Computer Security
a)
Use the best antivirus software,
which not only provides protection to your PC but also internet protection and
guards against cyber threats.
b)
Do not download un trusted email
attachments as these may carry harmful malware.
c)
Never download software from unreliable
sites as they may come with a virus that may infect your system as soon as you
install the software.
Information Security (infosec)
The processes and
methodologies which are designed and implemented to protect print, electronic,
or any other form of confidential, private and sensitive information or data
from unauthorized access, use, misuse, disclosure, destruction, modification,
or disruption.
Key principles of Information
Security
a)
Confidentiality:- Only authorized users
can access the data resources and information.
b)
Integrity:- Only authorized users should
be able to modify the data when needed.
c)
Availability:- Data should be available
to users when needed.
Security Threats
— A
risk which can potentially harm computer systems and organization.
— The cause could be physical such as someone
stealing a computer that contains vital data.
— The
cause could also be non-physical such as a virus attack.
Possible Security Threats
— Internal:
The threats include fire, unstable power supply, humidity in the rooms housing
the hardware, etc.
— External:
These threats include Lightning, floods, earthquakes, etc.
— Human:
These threats include theft, vandalism of the infrastructure and/or hardware,
disruption, accidental or intentional errors.
— Loss
or corruption of system data.
— Disrupt
business operations that rely on computer systems.
— Loss
of sensitive information.
— Unauthorized
access to computer systems resources such as data.
Malicious code (Malware)
— A
code developed by cyber attackers, designed to cause extensive damage to data
and systems or to gain unauthorized access to a network.
— Includes
computer viruses, worms, Trojan horses and spyware.
— Perform
a variety of different functions such as stealing, encrypting or deleting
sensitive data, altering or hijacking (taking control) core computing functions
and monitoring users' computer activity without their permission.
Types of malware
a)
A virus is the most common
type of malware which can execute itself and spread by infecting other programs
or files.
b)
A worm can
self-replicate without a host program and typically spreads without any human
interaction or directives from the malware authors.
c)
A Trojan horse is designed
to appear as a legitimate (valid) program in order to gain access to a system. Once
activated following installation, Trojans can execute their malicious
functions.
d)
Spyware is made
to collect information and data on the device user and observe their activity
without their knowledge.
e)
Keyloggers, also called system monitors,
are used to see nearly everything a user does on their computer. This includes
emails, opened web-pages, programs and keystrokes.
Protect a system from infection
a)
Never download files from unknown or
suspicious sources.
b)
Install antivirus software that features
automatic updates and has the capability to detect all types of infections.
c)
Delete spam and junk emails without
forwarding.
d)
Always scan a pen drive from an unknown
source for viruses before using it.
e)
Regularly back up your documents,
photos, and important email messages to the cloud or to an external hard drive.
In the event of an infection, your information will not be lost.
Security
mechanisms
— A
mechanism that is designed to detect, prevent, or recover from a security
attack.
— It
includes
— Authentication
Systems
— Firewalls
— Cryptography
— Antivirus
Software
— Backup
System
Authentication System
— Authentication
is the process of verifying the identity of a person or device.
— Authentication
system makes sure that right people enters the system and access the right
information.
— Types
of Authentication
— Password
— Biometric
Password
— A
set of secret characters or words used to authenticate access to a digital
system.
— Password
ensures that unauthorized users do not access the computer.
— Password
secures the data by protecting the data from unauthorized access.
— To
protect a system from unauthorized access, password should be kept in a system
which provides security to the system.
— A
password should be difficult to guess and determine and should be changed
regularly and memorized.
Any four criteria for strong
password are:
a)
Do not keep a password which can be
easily guessed such as date of birth, nickname, etc.
b)
Do not keep word as password that is
currently popular.
c)
Keep a password with mixture of alphabet
and numbers which is difficult to guess.
d)
Keep changing your password regularly.
Biometric
— Biometrics
are physical or behavioral human characteristics that can be used to digitally
identify a person to grant access to systems, devices or data.
— Examples
of these biometric identifiers are fingerprints, facial patterns and voice.
— Computers
and devices can unlock automatically when they detect the fingerprints of an
approved user.
— Apple's
Face ID (introduced with the iPhone X) authenticates users by facial
recognition.
— Retinal
scanners, which require an eye scan to allow authorized individuals to access
secure areas.
Firewall
— A
network security device, either hardware or software that monitors and filters all incoming and
outgoing network traffic based on an organization’s previously established
security policies.
— Firewall
blocks unwanted traffic as well as malicious software from infecting your
computer.
— Firewalls
helps to prevent unauthorized access.
— Software
firewalls are designed to protect a computer by blocking certain programs from
sending and receiving information from a local network or the Internet.
— Hardware
firewalls are found on most network routers and can be configured
through the router setup screen.
Cryptography
— A
technique of securing information and communications through use of codes so
that only those person for whom the information is intended can understand it
and process it.
— Thus
preventing unauthorized access to information.
— The
prefix “crypt” means “hidden” and suffix graphy means “writing”.
— A
message sent over the network is transformed into an unrecognizable encrypted
message known as data encryption. At the receiving end, the received message is
converted to its original form known as decryption.
— Cryptography
is used to secure and protect data during communication.
Features
of Cryptography
a)
Confidentiality: Information
can only be accessed by the person for whom it is intended and no other person
except him can access it.
b)
Integrity: Information
cannot be modified in storage or transition between sender and intended
receiver without any addition to information being detected.
c)
Non-repudiation: The
creator/sender of information cannot deny his or her intention to send
information at later stage.
d)
Authentication: The
identities of sender and receiver are confirmed. As well as destination/origin
of information is confirmed.
Encryption
— Encryption
is a process which transforms the original information into an unrecognizable
form.
— This
new form of the message is entirely different from the original message.
— That's
why a hacker is not able to read the data as senders use an encryption
algorithm.
— Encryption
is usually done using key algorithms.
— Data
is encrypted to make it safe from stealing. However, many known companies also
encrypt data to keep their trade secret from their competitors.
Decryption
— Decryption
is a process of converting encoded/encrypted data in a form that is readable
and understood by a human or a computer.
— This
method is performed by un-encrypting the text manually or by using keys used to
encrypt the original data.
KEY
DIFFERENCE BETWEEN ENCRYPTION AND DECRYPTION
a)
Encryption is a process of converting
normal data into an unreadable form whereas Decryption is a method of
converting the unreadable/coded data into its original form.
b)
Encryption is done by the person who is
sending the data to the destination, but the decryption is done at the person
who is receiving the data.
c)
The same algorithm with the same key is
used for both the encryption-decryption processes.
Antivirus software
— Antivirus
software is software designed to detect and remove virus from computer system
and ensures virus free environment.
— E.g.
Kaspersky, NAV, MSAV, McAfee, NOD 32 etc.
— Main
use of antivirus is to protect computer from viruses and remove viruses that
are detected and also protects data and programs from being corrupted.
Backup system
— It is the system of copying data and programs into
another location or creating a duplicate copy of it in a secured place.
— A copy of a file which is used in the event of the
original file being corrupted.
— Backup is vital to computer security system in order
to save the data from being lost or damaged due to accidental or intentional
harm. When data and software are lost or damaged, we can easily recover through
backup.
— These files are kept on hard disks, CDs and tapes and
on the internet.
Hardware Security
— The
security given to the machine and peripheral hardware from theft and from
electronic intrusion (interruption) and damage.
— Different
hardware security measures are:
a)
Regular Maintenance
b)
Insurance
c)
Dust free environment
d)
Protection from Fire
e)
Protection from Thief
f)
Air condition system
g)
Power Protection device (Volt guard,
Spike guard, UPS)
Regular Maintenance
— Computer
system need regular maintenance to keep the computer hardware in good working
condition and it also helps to find out problems in hardware and correct the
problems before they cause several damages.
— The
hardware components of computer systems are very delicate and gets damaged if
proper care is not taken.
— E.g.
CPU cooler not working properly and if we don’t repair or replace on time then
the computer system may get halted and can damage microprocessor.
— Another
E.g. Computer Hard disk which needs to be checked frequently in order to find
errors and keep in good condition.
Insurance
— A
means of protection from financial loss.
— If
a computer is damaged or stolen or any kind of harm done then we can claim for
the insurance amount and get the economic support.
Dust Free Environment
— Dust
particles can cause the failure of hardware components.
— Computer
room should be absolutely free from dust and air pollution.
— Use
dust cover to prevent our computer from dust particles.
Protection from Fire
— Due
to faulty wiring, loose connection, smoking in the computer room and overload
on power socket can cause fire in a room.
— Using
fire alarms, fire doors, fire detectors and fire extinguishers can minimize the
damage of hardware components and loss of information from fire.
Protection from Theft
— Use
of Lighting system, Grills on the windows, Safety Lock on the doors, Alarms,
CCTV (Closed Circuit Television) helps to protect from thieves.
Air Condition System
— A
system for controlling the temperature and humidity (wetness) of the air
— Maintains
suitable temperature or humidity in the computer room.
— Room
Temperature should be maintained between 210C to 240C.
Power Protection Device
— An
electric device that controls electric voltage and provides enough backup to the
computer system when there is power failure.
— Computer
needs 220 volts to 240 volts constantly.
— Some
common power protection devices are:
a)
UPS
b)
Volt Guard
c)
CVT
d)
Stabilizer
e)
Spike Guard
f)
Surge Suppressor
Why Power Protection Device needed?
— To
protect computer system from damage, expensive data loss and unnecessary down
time (is out of action or unavailable for use).
Volt Guard
— A
power protection device that provides constant output voltage to the computer
system in case of high input voltage coming from the source.
UPS
— UPS
is a battery supported power protection device which controls the electric
voltage and supplies clean and continuous power to the computer system even
during power failures.
— The importance of UPS in computer security system is
that it controls fluctuation of electric voltage and provides enough backup
electric power to the computer system when there is power failure.
Spike Guard
— A
device designed to protect electrical devices from voltage spikes.
— Automatically maintains a constant voltage level.
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