cyber world overview
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Online Certificate Course
on
Cyber LawCyber LawCyber LawCyber Law
PAPER 1: INTRODUCTION TO THE CYBER WORLD AND
CYBER LAW
PART A : CYBER WORLD - AN OVERVIEW
Prepared by
Mr. Kapil SoniAsst. Manager (Engineering)
OM Nanotech Pvt. Ltd.
Delhi.
FOR
THE INDIAN LAW INSTITUTE(Deemed University)
Bhagwandas RoadNew Delhi - 110001
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Table of contents
Cyber World: An Overview- Understanding the scope of computers in our daily life- Basic /Fundamental Principle of computer- The E Zone- Where did the computer come from?
33
334
What is a Computer Network? 4
Pre-Requisites of Internet Connection 13
Basic Working of ISP 16
Dialup Connection Provided by ISP 17
Broad-band Connections 18
What can we do with Internet 20
Security of Information: 21
Types of Threats 23
Prevent yourself from the Threats 24
Digital Signatures 25
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Cyber World: An Overview
This paper provides an overview of cyber world with reference to-
The Internet and online resources
Security of Information
Digital Signature
Understanding the scope of computers in our daily life
There is no doubt, that in todays world, computer are used
everywhere, when we mean everywhere, it could be your local shopping
center, computer center, be it your railway reservations, airlines reservation,
micro-wave ovens, even your phones. Institutions like banks, not only ease
the use of banks, but also give us flexibility to bank from virtually anywhere.
With a swipe from your plastic money (Debit/Credit Cards), it fetches
balance information from your banks account and there you go, you just
purchased the commodity without even bothering, how many gadgets,
complex security codes went through and did helped you to purchase.
Basic /Fundamental Principle of computerWhen they (electronic gadgets) receive an input, they definitely give an
output after some calculations, whether we realize or not. Eg: Our Caller Id
Telephone in Fixed Line, not only tells the number but it is also able to tell the
name of the person. It stores and recalls, whenever the bell rings, it knows
what to be displayed on screen of your telephone.
The E ZoneThere could be numerous such examples where our life has been
attached with e. Be it mail that got converted to e-mail, your banking
became e-banking, commerce became e-commerce, and so on. This e- stands
for Electronics. Now that makes better sense, Electronic mail called as E-Mail.
Electronic Banking called as E-Banking etc.
Similarly, when we speak of Cyber, it is a prefix, derived from
cybernetics (a Greek word meaning "the art of steering"), used to describe the
entire range of things made available through the use of a computer. Earlier
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it was used in fiction stories, but now its commonly used. For example:
cyber-phobia is an irrational fear of computers, cyberspace is the virtual
(nonphysical) space created by computer systems.
But when we talk about some terms like cyber-space in terms of our
scope, we combine not only the humans, computers (hardware and/orsoftware), but also to the extent that one (computer) is almost capable to do
that. Mostly, this term is associated with science fiction, as simply as a
computer is not capable of thinking.
Where did the computer come from?As we say, necessity is the mother of invention and un-fortunately, the
computers are invention of Cold Wars. In beginning, they are humongous,
very large in size, would cover a size of a football ground, and may be bigger.
But as computers can be trusted more than humans if we give a repeated task,
it definitely supersedes humans in certain area. As a matter of fact, they
instate discipline in work. One has to follow certain guidelines to attain a job
done from computers. Let us take a small example, when banking was done
manually, Customers could have a personal touch on the banker, but since
computers are in place, it would work at same speed even if its a new
customer, or his relative. Im sure, flight bookings and their management
couldnt have been better as we have the facility to book, tickets, get best
fares. This facility is not only extended to our computers at home, but also
extended to our mobile phones which is always in network.
Moreover, the art of communication, which helps in transfer of information /
data from any place to any place. Gone are the days when one had to make a
school projects, business presentations, now-a-days, one can search projects,
themes and then continue to add wings to ones concept.
What is a Computer Network?Computer Network: To be able to communicate and share resources
(knowledge or information, hardware equipments, software etc) between two
or more computers.
One just has to share the equipment/information, and it becomes
available to others. Telephones were the one of the first electronic gadgets,
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which helped humans to interact with each other. However, it could only
send voices across. You can just dial the desired phone number and you can
access anyone else who is connected to the same network and is available.
There was one more invention Radio. But it could communicate only
one-way. We may not put radio and television in category of Television. AndCyber Space one of the best and economic way to bridge gap between each
other, it is irrespective of physical boundaries and distances.
Have you ever imagined, that if a person in country A makes a call to
another country B, the call has to go through various networks of telephone
exchanges, however when you speak from here, the other person (if both use
same language to communicate) is also able to hear and respond accordingly.
This is irrespective of the path that it took. This happens because even if they
use different machines / gadgets, they have to follow same set of rules, just
like on road, one has to follow traffic rules to avoid chaos, and it does not
depend on which vehicle you are driving.
Similarly, in computer networking, there are a few standard sets of
rules which both (or more than two) have to follow if they want to network
with each other. These set of rules are also called as Protocol.
Protocol: A protocol is a convention or standard that controls or enables the
connection, communication, and data transfer between two computing
endpoints.
Few Protocol Examples:
# Name Short Description Uses
1. IP Internet Protocol The Internet Protocol (IP) is a data-oriented protocol used for
communicating data across apacket-switched internet work.
2. UDP User DatagramProtocol
User Datagram Protocol (UDP) isone of the core protocols of theInternet protocol suite. Using UDP,programs on networked computerscan send short messagessometimes known as datagrams(using Datagram Sockets) to one
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another. UDP is sometimes calledthe Universal Datagram Protocol.
3. TCP TransmissionControl Protocol
The Transmission Control Protocol(TCP) is one of the core protocolsof the Internet protocol suite. TCPprovides reliable, in-order delivery
of a stream of bytes, making itsuitable for applications like filetransfer and e-mail. It is sometimesreferred to as "the TCP/IP protocol
suite."
4. DHCP Dynamic HostConfiguration
Protocol
Dynamic Host ConfigurationProtocol (DHCP) is a protocol used
by networked devices (clients) toobtain IP addresses and otherparameters such as the defaultgateway, subnet mask, and IP
addresses of DNS servers from aDHCP server. The DHCP serverensures that all IP addresses areunique. IP address poolmanagement is done by the serverand not by a networkadministrator.
5. HTTP Hypertext TransferProtocol
HTTP is a request/responseprotocol between a client and aserver. The client making an HTTPrequest - such as a web browser,
spider, or other end-user tool. Theresponding server - which stores orcreates resources such as HTMLfiles and images - is called theorigin server.
6. FTP File Transfer Protocol FTP or File Transfer Protocol isused to transfer data from onecomputer to another over theInternet, or through a network.
7. Telnet Telnet RemoteProtocol
TELNET (TELecommunicationNETwork) is a network protocol
used on the Internet or local areanetwork (LAN) connections.
8. SSH Secure Shell RemoteProtocol
Secure Shell or SSH is a networkprotocol that allows data to beexchanged over a secure channelbetween two computers.Encryption providesconfidentiality and integrity ofdata. SSH uses public-key
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cryptography to authenticate theremote computer and allow theremote computer to authenticatethe user,
9. POP3 Post Office Protocol-3
In computing, local e-mail clientsuse the Post Office Protocol version
3 (POP3), an application-layerInternet standard protocol, toretrieve e-mail from a remoteserver over a TCP/IP connection.
Eg: Outlook Express retrievesemails from Email Server with helpof POP3 Protocol
10. SMTP Simple Mail TransferProtocol
Simple Mail Transfer Protocol(SMTP) is the de facto standard fore-mail transmissions across theInternet.
There are different types of networks classified by scale/scope:
1. PAN (Personal Area Network): A personal area network (PAN) is a
computer network used for communication among computer devices close to
one person. Some examples of devices that may be used in a PAN are:
printers, fax machines, telephones, PDAs, or scanners. The reach of a PAN is
typically within about 20-30 feet (approximately 4-6 Meters). PANs can be
used for communication among the individual devices (intrapersonalcommunication).
2. LAN (Local Area Network): A network covering a small geographic area,
like a home, office, or building. Current LANs are most likely to be based on
Ethernet technology. For example, a library will have a LAN for users to
connect to the internet.
3. CAN (Campus Area Network): A network that connects two or more
LANs but that is limited to a specific and contiguous geographical area such
as a college campus, industrial complex, or a military base. A CAN, may be
considered a type of MAN (metropolitan area network), but is generally
limited to an area that is smaller than a typical MAN.
4. MAN (Metropolitan Area Network): A Metropolitan Area Network is a
network that connects two or more Local Area Networks or Campus Area
Networks together but does not extend beyond the boundaries of the
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immediate town, city, or metropolitan area. Multiple routers, switches & hubs
are connected to create a MAN.
5. WAN (Wide Area Network): A WAN is a data communications network
that covers a relatively broad geographic area (i.e. one city to another and one
country to another country) and that often uses transmission facilitiesprovided by common carriers, such as telephone companies. WAN
technologies generally function at the lower three layers of the OSI reference
model: the physical layer, the data link layer, and the network layer.
Different combinations of above types, broadly can be done as:
1. Intranet: It uses simple protocols (like Internet Protocol) and IP Based
tools (like web browsers), which is controlled by a single administrative
entity. Eg: A typical Office Network, where all users can share common
resources like printer, but only limited users are allowed to access Internet.
2. Extranet: An Intranet which has a limited connections to other Network.
Eg: A company may give some access to its intranet, but at the same time, this
connection may not be considered as trusted from security point of view.
3. Internet: Internet is a worldwide, publicly accessible series of
interconnected computer networks that transmit data by packet switching
using the standard Internet Protocol (IP). It is a "network of networks" that
consists of millions of smaller domestic, academic, business, and government
networks, which together carry various information and services, such as
electronic mail, online chat, file transfer, and the interlinked web pages and
other resources of the World Wide Web.
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Depending upon number of computers and kind of complexities
involved, it is broadly divided in two kinds. There are two basic reference
models:
Internet Protocol Suite (IPS)
OSI Model / 7-Layer OSI Model
a. Internet Protocol Suite (IPS)
The Internet protocol suite is the set of communications protocols that
implement the protocol stack on which the Internet and most
commercial networks run. It has also been referred to as the TCP/IP
protocol suite, which is named after two of the most important
protocols in it: the Transmission Control Protocol (TCP) and the
Internet Protocol (IP), which were also the first two networking
protocols defined. Today's IP networking represents a synthesis of two
developments that began to evolve in the 1960s and 1970s, namely
LANs (Local Area Networks) and the Internet, which, together with
the invention of the World Wide Web by Tim Berners-Lee in 1989, have
revolutionized computing.
The Internet Protocol suitelike many protocol suitescan be
viewed as a set of layers. Each layer solves a set of problems involving
the transmission of data, and provides a well-defined service to the
upper layer protocols based on using services from some lower layers.
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Upper layers are logically closer to the user and deal with more
abstract data, relying on lower layer protocols to translate data into
forms that can eventually be physically transmitted.
HTTP Application
TCP Transport
IP Network
Ethernet Link
RJ 45 / CAT5 Physical
b. Open System Interconnection (OSI)
The Open Systems Interconnection Basic Reference Model (OSI
Reference Model or OSI Model for short) is a layered, abstract
description for communications and computer network protocol
design. It was developed as part of the Open Systems Interconnection
(OSI) initiative and is sometimes known as the OSI seven layer model.
From top to bottom, the OSI Model consists of the Application,
Presentation, Session, Transport, Network, Data Link, and Physical
layers. A layer is a collection of related functions that provides services
to the layer above it and receives service from the layer below it. For
example, a layer that provides error-free communications across a
network provides the path needed by applications above it, while it
calls the next lower layer to send and receive packets that make up the
contents of the path.
USER (Transmit) USER (Receive)
Layer 7 Application Layer
Layer 6 Presentation Layer
Layer 5 Session Layer
Layer 4 Transport Layer
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Layer 3 Network Layer
Layer 2 Data link Layer
Layer 1 Physical Layer
The 7 Layers of OSI Model
In short, when user wants to connect to a web-server (eg:
www.google.com), he need an application (Internet Explorer / Godzilla
Browser etc), common protocol, and a physical link (or secured link)
between two computers. Short definitions/functions are given in thetable below:
Layer Name Description
Layer7
Application This layer supports application and end-user processes.Communication partners are identified, quality of serviceis identified, user authentication and privacy areconsidered, and any constraints on data syntax areidentified. Everything at this layer is application-specific.This layer provides application services for file transfers,
e-mail, and other network software services. Telnet andFTP are applications that exist entirely in the applicationlevel. Tiered application architectures are part of this layer.
Layer6
Presentation This layer provides independence from differences in datarepresentation (e.g., encryption) by translating fromapplication to network format, and vice versa. Thepresentation layer works to transform data into the form
that the application layer can accept. This layer formatsand encrypts data to be sent across a network, providingfreedom from compatibility problems. It is sometimes
called the syntax layer.
Layer5
Session This layer establishes, manages and terminatesconnections between applications. The session layer setsup, coordinates, and terminates conversations, exchanges,and dialogues between the applications at each end. Itdeals with session and connection coordination.
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Layer4
Transport This layer provides transparent transfer of data betweenend systems, or hosts, and is responsible for end-to-enderror recovery and flow control. It ensures complete datatransfer.
Layer
3
Network This layer provides switching and routing technologies,
creating logical paths, known as virtual circuits, fortransmitting data from node to node. Routing andforwarding are functions of this layer, as well asaddressing, internetworking, error handling, congestioncontrol and packet sequencing.
Layer2
Data Link At this layer, data packets are encoded and decoded intobits. It furnishes transmission protocol knowledge andmanagement and handles errors in the physical layer, flowcontrol and frame synchronization. The data link layer isdivided into two sublayers: The Media Access Control(MAC) layer and the Logical Link Control (LLC) layer. The
MAC sublayer controls how a computer on the networkgains access to the data and permission to transmit it. TheLLC layer controls frame synchronization, flow control anderror checking.
Layer1
Physical This layer conveys the bit stream - electrical impulse, light
or radio signal -- through the network at the electrical andmechanical level. It provides the hardware means ofsending and receiving data on a carrier, including definingcables, cards and physical aspects. Fast Ethernet, RS232,and ATM are protocols with physical layer components.
The above technology comprises a basic network where two or more
computers interact.
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The Internet: A complex representation of Internet. Inset: A magnified portion that shows aNetwork System of a small Organization.
Pre-Requisites of Internet Connection
1. You need to have a computer with Network Card or Telephonic modem
depending upon type of connection that you plan to take from your ISP.
Network Cards are usually built into your computer these days, however,
you have to specifically ask for Telephone Modem from your Computer
Hardware Vendor.
2. You also need a Internet Service Provider, and means to connect to your
Internet Service Provider (ISP).
3. You need a User Name (Provided by your ISP).
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4. To avoid someone else use your Internet Plans User Name, you need to
protect it with a password.
5. You need to have a modem:
i. Telephonic Modem
ii. DSL Modemiii. Cable Modem
6. You need an application where you can view a website or download
information / data. This is called a Web-browser. Most popular web-
browsers:
i.Internet Explorer: It is a tool, which is provided along with Microsoft
Windows. You can click / double click on the icon for application
and type the website address in the address bar. As it downloads the
website information, it starts displaying the website information in
Web-Page Information
ii. Mozilla Firefox: Mozilla Firefox is a tool which also helps in
viewing Website information, however, it is created by a an
organization which is global community and public benefit
organization dedicated to improve Internet experience for people
everywhere. It has its own unique interface. However the concept
remains the same.
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Once you fulfill the above criteria, you are ready to get connected to
hundreds, thousands of computers and servers available worldwide. In cyber
terms, we also call it as online. Online When our computer (or any other
gadget) is connected to World Wide Web (WWW) and can view websites,
download information/data, we say it as online. Usually term online is
associated when we are connected to Internet.
Let us discuss the above pre-requisites. ISP:
ISP or we also call it as Internet Service Provider or also called as IAP
(Internet Access Provider). It is an organization, which provides the end-user
(consumer or business access) an access to World Wide Web the Internet.
Earlier ISPs were run and maintained by Telephone providers. There were
mainly two reasons they could only provide the telephonic network which
was required by any Service Provider, the other reason was that they were
also able to control / monitor to a greater extent. However, now as cost of
infrastructure has gone down considerably, there are more private venturous
who came up with their own ISP. These days you would lot kind of ISP
which are broadly categorized as:
a) Dialup
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b) Broadband
i. DSL Broadband
ii. Cable Broadband
The major criteria for differentiating different type of Internet
connections are speed.
These Service providers give you an Access System in which the ISP
gives you a unique identity. This way, ISP is able to log and maintain your
usage, and thus able to charge as per your plan/usage. It usually comprises
of a unique User Name accompanied by a password, which prevents others to
use your unique User Name. Some ISP even maintains your Network Cards
Hardware Code apart from user name and password. In such cases, if you
have that connection in your desktop computer, you cannot connect the same
on your Laptop. You will have to request your ISP to given you another
connection which enables you to connect to other computer (in this case a
Laptop).
Basic Working of ISPTo get Internet access, End user first has to establish a connection with ISP
Server. This server then validates you as a user by first checking if your
unique user name matches with the list that server has; and then the
password. If both your user name and password matches, then it checks
your account validity and if you have enough balance to use Internet Services
(Browsing, downloading etc), you are given access. This enables you to make
use of Internet Services.
ISPs mainly provide two kinds of accounts:a) Hourly Plan: In case of hourly plan, it does not matter on how much you
download or surf. What matters is the number of hours. This kind of plan is
more suitable, if you have regular task of download.
b) Usage / Download & Upload Plan or also called as MB (Mega Bytes) Plan:
In these plans, you purchase few Mega Bytes of Information download ie, you
are not paying for hour usage, one pays for Bytes. It can be an information
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download or a website content that gets downloaded. In case of usage /
download plans, it does not matter how long you open the site, but even if
you refresh (fetching same information again) same site several times, you
would be paying for each refresh you do. One would prefer this plan if you
are searching and you have to gather most of information by reading.c) Un-limited: These connections are expensive than the above two, but one
has no limits on usage or downloads from Internet. In some cases, un-limited
connections are limited with speed factors, eg: you can get an internet
connection which would be un-limited but will not be able to exceed speed of
64kbps.
Now lets us discuss something about dialup and broadband setups:
Dialup Connection Provided by ISP
To connect to a Dialup Internet connection, of course, ensure that your
computer is on and ready. Your computer should have a dialup modem and
necessary software for modem installed in your computer.
You will be given a phone number from your ISP. This phone number
directly connects your computer to ISP Login Server. This is done with help
of a special instrument Modem. It translates computer language (also
known as digital language) to Analog Language (the signal that travels
through Telephone lines) and vice-versa. Once initiated, the server gives our
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computer a fax tone. The server then prompts us to input User Name and
password. After that the server knows that you are a valid user, it proceeds
further and gives you access to Internet. However meanwhile you are
connected to Internet, you are at the same time being billed for phone talk
time. In other words, making Internet connection gets charged in two ways:a) Talk Time (As Modem dials the ISP number and gets connected)
b) ISP Charges. Apart from Telephone Talk time, we also have to pay for the
Internet services, which is the other cost than the Talk Time.
Once we are done with our Internet, we can then logout / disconnect.
The phone line now gets free for our normal usage.
Advantage: It requires lesser investment in terms of hardware. In earlier
times, it was the cheap and best way to get connected.
Disadvantage: Firstly, we have to pay for both, telephone usage and Internet
usage. Secondly, it is very slow. Thirdly, one can use it for either one
purpose phone or Internet purpose. Even if there is a minor disturbance in
phone line, you may never get connected or sometimes it makes Internet
connection very slow. If you are not able to get connected, the second time
you try is basically a second call that you have made. In other words, each
time when you get a Fax Tone, you have called up the server those many
times, this is regardless if you were able to get connected to Internet or not.
Broad-band Connections
S litter
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Broadband Internet or Broadband is almost similar in working as a
dialup setup. However, in most of ISPs, you have an option to key-in the user
name and password every time, in other words, just turn on computer and
modem, and you are connected. No hustles of typing your user name
password as it is remembered by your DSL-modem (DSL Digital SubscriberLine). It is much faster A conventional dialup modem may give you speeds
up to 54kbps (kilo bits per second), whereas minimum speed provided by
broadband is 64kbps, and can go up to 2Mbps. These days the most common
speeds are 128kbps and 256kbps. Small office / home office (SOHO) usually
uses 512kbps, which is sufficient enough to share Internet connection for up
to 10~15 computers.
Moreover, we can use our phone line as well as Internet at the same
time. They both use same connection (wires and cables), but with help of
splitter and new modem design, both are treated separately. Both have
different accounting, thus your talk-time and Internet Usage can be
charged as per usage.
Advantages: Better speed, more stable connection. Easy to use as compared
to telephonic modem ISP. Minimum speed is 64kbps which is faster than
Dialup Modem ISP. One can use phone line and Internet on the same
connection and same ISP. In-case of Cable Modem, one can have TV and
Internet working on same setup.
Disadvantage: The modem cost is slightly higher than a dialup modem. It
also requires a separate power adaptor. As in some cases it is always on, one
may un-intentionally download files (Eg: Updates etc that may not be
necessary). These factors accounts for billing factors un-knowingly.
There are several other ways as well:
ISDN: Integrated Service Digital Network
Rural Internet
Satellite Internet
Cellular Broadband
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What can we do with Internet
The basic purpose of Internet:
1. Information / Knowledge:
a. Share Information / data and Access to infinite knowledge: Search
Options eg: www.google.com, www.yahoo.com, www.amazon.com etc.
b. Forums: These are special sites, which are dedicated for
discussions. You may put your query on these websites, and once
some one has a solution, he/she would share that
experience/knowledge/solution with you.
2. Communication:
a. Email: This has brought a revolution in the way we communicate.
It has almost replaced our existing snail-mail system (the conventionalLetter System). Most of the business, formal or informal
communications are being done through this Electronic Mail.
b. Chats: Commonly used only for entertainment/relaxation, or
online live text communication. It requires a small tool that enables
people to communicate with each other through written text.
Difference between online chat and email is, that both person(s)
communicate with each other at the same time. It is also important
that both person are online and logged in at the same time so that
they can communicate with each other at the same time. They also
need to have same type of tool. Eg: yahoo messenger should be
installed on both computers. If one has yahoo and other one has
hotmail, they will not be able to chat amongst themselves.
c. Video Conferencing: This is an extension of Chat session. Few of
the tools support Live Video images to go across. For this both parties
should have a Web-cam, else only one person would be able to view.
3. Entertainment:
a. Book Travel Tickets: You may visit a travel page, and there you
will be able to search best prices for your airfare. Railways also offer a
website which enables us to book our tickets and get it delivered to our
doorstep.
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b. Play online-games: There are lot of multi-user games available. We
definitely need a high-speed Internet connection for this as they
required to be in touch all the time.
4. Business
a. Advertise: Most of the free Email Providers usually bring in lot ofadvertisements. This is needed for them to keep running and
maintaining their servers.
b. Online-Shopping: Now without going to stores, you can find the
best and cheapest items. You can even compare there features. You
can go to online shopping on various sites eg: www.ebay.in,
www.indiaplaza.com, www.rediff.com etc.
c. Online-Banking: Now you can manage your account online as well.
You dont need to go to bank for most of transactions. Infact, ATMs
(Automatic Teller Machine) and Computer banking (or E-Banking) has
almost made us forget Who is working in our bank branch. You can
go to any bank and deposit or withdraw money, and the balance is
reflected almost instantly. All these branch computers are actually
linked to a central Banks Server Computer. Once they are updated, all
that gets reflected in your respective accounts.
d. Extend your office (or) Access your office computer (with help of
special tools): With help of few tools, you can actually work on your
office computer without actually being there. All you need is that your
office computer and your computer (from where you wish to work)
should have an Internet access and a computer. It also needs a special
application that enables this possibility and keeps it secured enough.
Security of Information:Since times, it is always very important to secure information. There
were several ways in which messages were secured. Some of the most
common examples was, When ever any message was sent through a
messenger, it will be sealed by special material. This used to ensure that no
one has read the message in between. To overcome this limitation, the
messages were encoded on a strip of cloth. It then was wrapped on a cylinder
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with specified diameter. A message was written on it, to make it more
complex, further text were also written so that it makes difficult to make out
what was written on it. These two objects, the cylinder and piece of cloth
were sent via different messengers. When it reached the destination, both had
to be combined to read the correct message. See illustration:
As you can see in the illustration, it does not reveal message when
cloth is spread. But when it will be wrapped again on same diameter
cylinder, one can read the required message. To make us understand easily,
the word WORLD PEACE is in bold. Even today, a similar technology is
used to save the original message. It is wrapped on a special sequence of
characters where. This process of making a message secure is also called as
encrypting. When this message is converted in normal form so that it is easily
readable, then this process is called as de-encryption.
Threats to InformationThe biggest threat to Information stored in a computer is VIRUS. In
Latin, it means toxic or poison. It is a computer program that can copy itself
and infect a computer without permission or knowledge of user. As common
viruses infect people through some media, air, touch, blood transmission etc;
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similarly a Computer virus also spreads through exchange of information
through Floppy, CD media, USB Pen Drives or Internet (Email, websites,
downloads). They may make our computer slow, freeze it to perform only
few operations, delete data files, or even leave our computer as Not
Bootable.There is one more threat which is even more painful and time
consuming. A Virus-Hoax. People in threat of a virus, usually format (Erase
everything on a disk) and re-install (Eg: Operating System Re-install like
Windows, Linux etc). This is a lengthy and time-consuming process. Just
imagine a Network Administrator had to re-do the whole Server again. This
being a major factor in down-time for the users who were trying to access the
Servers.
Despite of various options available, to prevent computer threats, still
there are chances of your computer getting a virus. The best policy is
Prevention is better than cure!
Types of ThreatsThere are several type of threats:
a) Virus: Computer programs that travel through floppy, CDs, Pen Drives,
Games (Usually Demo Versions), Internet.
b) Spyware: It is a computer program that gets installed without
informing/knowledge of the user into a computer and takes partial control of
the computer. They reside in the computer and monitor, collect personal
information, Install additional software, redirecting to any website.
Spywares usually gets into computer from websites or Junk Emails.
c) Rootkit: It is a program (or a combination of programs) designed to take
fundamental control of a computer system, without authorization of user. It
may allow unauthorized users to act as system Administrator on your
computer; and thus take full control of your computer system.
d) Worm: It is a self-replicating computer program. It usually uses a
network to send copies of itself to other computers attached on the same
network without informing the user. They may corrupt files or simply choke
the bandwidth (Speed) of network.
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e) Trojan Horses: A computer program that appears to perform certain
action, but in fact performs some other actions, as a virus would do. Its
usually hidden with another free-ware utility tool. Eg: You may download a
free alarm software from a website. But it actually gets in your computer and
destroys your computer files.
Prevent yourself from the Threats
You can prevent but not avoid virus threats and problems. The best
way is to Install a Good Antivirus Program with all features and keep it
updated. -- Why Updated? Let us understand by an example: You
purchased an Antivirus, Anti-Spyware Software on 1.Dec.2006 and installed it
successfully. There are hundreds of Viruses Spywares, Trojans etc creatednew on Internet in every 24 hrs. Now, your Antivirus/Anti-spyware
Programs would not be aware of all the viruses, Spyware, Trojans that were
created after 1st of Dec 2006. Then how are you protected? - In this situation
you are only protected till you are not attacked by the latest.
It is very important for anyone who uses his/her computer; to keep
their Antivirus/Anti-Spyware Program updated all the time.
From time to time, Software companies keep on releasing fixes.
When any operating system / computer program is written, it comprises of
several thousands of lines of code. There may be some un-thought possibility
left while creating that computer software. Whenever these vulnerable
threats are realized, a new revised patch (small software code to fix known
problem) is release from the software company. These are given different
names eg: Windows NT Server came with Service Packs (SP1, SP2, SP3 etc).
Windows 98 released Windows 98 SE (second edition). Windows XP released
Windows XP SP2 (Service Pack 2). Antivirus release its new patches or
updates almost daily so that their database of list of viruses and techniques
to handle them is always ready to defend with latest threats.
One should avoid using free or trial software: simply because they
may not be able to avoid most of the threats and it is never provided with
complete functionality. Eg: It may detect a virus in your computer, but may
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not remove virus from your computer. It puts you in jeopardy whether
you should purchase an ant virus right away or live with that virus. You may
not prefer to purchase it online as if your computer is hacked (someone else
monitoring your personal details or capturing your credit card numbers and
password), you may be in a greater loss by typing your credit card details!!!One should also avoid use of two different ant viruses at the same
time. An Anti virus resides in special place in memory, similar to a virus
most of time.
The second Antivirus may always give you false alarms of suspicious
activity going one in the computer.
If you are going to do online shopping/ banking, make sure that
address in the address-bar starts with https://. This ensures that
you are opening a Secured Website. You should also ensure that the site has
right spellings and proper grammar. Some are also able to fake sites
(Phishing).
You should never respond to email where someone is asking your
bank details and personal details, unless you are very sure upon it. Banking
websites never ask your personal details unless you are logging into their
website.
Digital Signatures
The traditional ways used in our common lives are use of stamp and
seals. These with witnesses increase genuineness of a document. So that
others cannot access this document, it has to be kept in treasure. However,
even then these documents are prone to several threats. Similarly, in
computers or cyber space, we can use digital signature to make our
documents secure.
A digital signature is an electronic signature that can be used to
authenticate the identity of the sender of a message or the signer of a
document, and possibly to ensure that the original content of the message or
document that has been sent is unchanged. Digital signatures are easily
transportable, cannot be imitated by someone else, and can be automatically
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time-stamped. The ability to ensure that the original signed message arrived;
means that the sender cannot easily repudiate it later.
A digital signature can be used with any kind of message, whether it is
encrypted or not, simply so that the receiver can be sure of the sender's
identity and that the message arrived intact. A digital certificate contains thedigital signature of the certificate-issuing authority so that anyone can verify
that the certificate is real.
Let us understand its working by an example: Assume you were
going to send the draft of a contract to your lawyer in another town. You
want to give your lawyer the assurance that it was unchanged from what you
sent and that it is really from you.
You write the contract in your email. Using special software, you
obtain a message hash (mathematical summary) of the contract. You then use
a private key that you have previously obtained from a public-private key
authority to encrypt the hash.
The encrypted hash becomes your digital signature of the message.
(Note that it will be different each time you send a message.) At the other end,
your lawyer receives the message. To make sure it's intact and from you,
your lawyer makes a hash of the received message. Your lawyer then uses
your public key to decrypt the message hash or summary. If the hashes
match, the received message is valid.
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