Question Paper Computer Fundamentals and PC Software (BC111): October 2007 Section A Answer any two from the four questions given below: marks) 1.
a.
Explain in brief the generations of computers.
b. c.
Give a brief overview of computer hardware. Define software. State different types of software used in computers.
(2
×
20 = 40
(5 + 10 + 5 = 20 marks)
2.
3.
a.
Explain the procedure for drawing objects in MS-POWERPOINT.
b. c. a.
Explain the procedure for modifying objects in MS-POWERPOINT. Explain the procedure for inserting the clip-art feature in MS-POWERPOINT. (6 + 6 + 8 = 20 marks) What is a spread sheet and explain the procedure for creating a worksheet?
b. c.
Explain in brief how to format a worksheet. Give a detailed note on operators and operands in MS-EXCEL. (5 + 5 + 10 = 20 marks)
4.
a.
Explain briefly the procedure of creating tables in MS-WORD.
b. c.
Give a note on how the tables can be formatted in MS-WORD. Explain the concept of Auto format of tables. (5 + 10 + 5 = 20 marks)
Section B Answer any two from the three questions given below: marks) 5.
(2
×
10 = 20
State the different threats to computer security. Suggest the measures to counter these threats. (10 marks)
6.
What are the key elements of a Windows Desktop? Give a note on these key elements. (10 marks)
7.
Define a pivot table. Explain briefly the procedure of constructing pivot table in MS-EXCEL. (10 marks)
Section C Answer any two from the four questions given below: marks) 8.
(2
×
20 = 40
Explain in detail the concept of Windows Explorer. (20 marks)
9.
Explain in detail how to create a Macro in MS-WORD. (20 m arks)
10.
Define Cryptanalysis. Explain in detail the different types of attacks on cryptosystems. (20 marks)
11.
Explain in detail the concept of managing files and folders in Windows. (20 marks) END OF QUESTION PAPER
Suggested Answers Computer Fundamentals and PC Software (BC111): October 2007 Section A 1.
a.
Computer Generations First Generation Computers (1940 to 1956) The first generation of computers was characterized by vacuum tubes in the circuitry and magnetic drums for memory. These computers were enormous in size, used great deal of electricity and were expensive to operate. They also had limited storage capacity. First generation computers relied on machine language (binary-coded program) to perform operations and could solve only one problem at a time. Punched cards and paper tapes were used to input data and instructions, and output was displayed on printouts. Early computers like ENIAC, EDVAC and UNIVAC can all be classified as first generation computers. computers. Second Generation Computers (1956 to 1963) In the early 1950s, the discoveries of Transistor and Magnetic core memory changed the image of computers – from unreliable to highly reliable machines with increased capability, and higher storage capacity. The transistor was far superior to the vacuum tube, allowing computers to become smaller in size, cheaper, reliable and more energy efficient. Though transistor still generated a great deal of heat, it was a substantial improvement over the vacuum tube. Second generation of computers was also characterized by allowing programmers to specify instructions in symbolic (or assembly) language rather than cryptic binary machine language. High level programming languages like COmmon Business Oriented Language (COBOL) and FORmula TRANslation (FORTRAN) were also being developed at this time. Due to the increase in the cost of expanding programming, these machines were expensive to purchase and operate. Such computers were, therefore, mostly found in large computer centres or government/private laboratories with many programmers and support professionals. Third Generation Computers (1964 to 1971) The development of Integrated Circuit by Jack Kilby, an engineer with Texas Instruments, in 1958, was the hallmark of the third generation of computers. Punched cards and printouts gave way to devices like keyboards and monitors making it easier for the user to interact with the computer. Computer manufacturers could provide a range of accessories like the cathode ray tube display devices, page printers, consoles etc. Existence of an operating system allowed the device to run various applications at one time with the central program monitoring the memory. For the first time, computers were being widely used in business for areas like : •
Accounting
•
Payroll
•
Billing
•
Tracking Inventory, etc.
Third generation computers were substantially smaller and cheaper than their predecessors. Fourth Generation Computers (1971 to present) The trend in 1970s was to move from single-purpose but powerful computers towards cheaper computer systems that could support a large range of applications. A new revolution in computer hardware came about which could shrink the computer logic circuitry and its components using the Large Scale Integration (LSI) technology. Hundreds of components could now fit onto a single chip. In the 1980s, Very Large Scale Integration (VLSI) squeezed hundreds of thousands of components onto a single chip. This shrinking trend continued and led to the introduction of personal computers (PCs) – programmable machines that are small enough and inexpensive so that these can be purchased and used by individuals. Companies like Apple Computers and IBM introduced very successful PCs. The IC technology was not only used to construct the processor, but also for the construction of memory. The first memory chip was constructed in 1970 and could hold 256 bits.
Fifth Generation Computers (the Road Ahead) The fifth generation of computers characterized by artificial intelligence is in the process of development. The goal here is to develop devices that are capable of learning and responding to natural language input. This generation of computers is using new technologies in very large scale integration, along with new programming languages and will be capable of amazing feats, in the area of artificial intelligence, such as voice recognition. b.
Computer hardware Computer hardware is the physical part of a computer,(not to be confused with software which is not physical) including the digital circuitry, as distinguished from the computer software that executes within the hardware. The hardware of a computer is infrequently changed, in comparison with software and data, which are "soft" in the sense that they are readily created, modified or erased on the computer. Firmware is a special type of software that rarely, if ever, needs to be changed and so is stored on hardware devices such as read-only memory (ROM) where it is not readily changed (and is therefore "firm" rather than just "s oft"). Most computer hardware is not seen by normal users. It is in embedded systems in automobiles, microwave ovens, electrocardiograph machines, compact disc players, and other devices. Personal computers, the computer hardware familiar to most people, form only a small minority of computers (about 0.2% of all new computers produced in 2003). Personal computer hardware A typical Personal computer consists of a case or chassis in desktop or tower shape and the following parts: Typical Motherboard found in a computer •
Motherboard or system board with slots for expansion cards and holding parts •
Central processing unit (CPU) -
•
Random Access Memory (RAM) - for program execution and short term data storage, so the computer does not have to take the time to access the hard drive to find the file(s) it requires. More RAM will normally contribute to a faster PC. RAM is almost always removable as it sits in slots in the motherboard, attached with small clips. The RAM slots are normally located next to the CPU socket.
•
Basic Input-Output System (BIOS) or Extensible Firmware Interface (EFI) in some newer computers
•
•
Computer fan - used to cool down the CPU
Buses -
PCI
-
PCI-E
-
USB
-
Hyper Transport .
Power supply - a case that holds a transformer, voltage control, and (usually) a cooling fan
•
Storage controllers of IDE, SATA, SCSI or other type, that control hard disk, floppy disk, CD-ROM and other drives; the controllers sit directly on the motherboard (on-board) or on expansion cards
•
Video display controller that produces the output for the computer display. This will either be built into the motherboard or attached in its own separate slot (PCI, PCI-E or AGP), requiring a Graphics Card.
•
Computer bus controllers (parallel, serial, USB, FireWire) to connect the computer to external peripheral devices such as printers or scanners
•
Some type of a removable media writer: •
•
•
CD - the most common type of removable media, cheap but fragile. -
CD-ROM Drive
-
CD Writer
DVD -
DVD-ROM Drive
-
DVD Writer
-
DVD-RAM Drive
BD
•
•
•
-
BD-ROM Drive
-
BD Writer
•
Floppy disk
•
Zip drive
•
USB flash drive AKA a Pen D rive, memory stick
•
Tape drive - mainly for backup and long-term storage
Internal storage - keeps data inside the computer for later use. •
Hard disk - for medium-term storage of data.
•
Disk array controller
Sound card - translates signals from the system board into analog voltage levels, and has terminals to plug in speakers. Networking - to connect the computer to the Internet and/or other computers •
Modem - for dial-up connections
•
Network card - for DSL/Cable internet, and/or connecting to other computers.
Other peripherals . In addition, hardware can include external components of a computer system. The following are either standard or very common.
•
•
•
c.
Input or Input devices •
Text input devices Keyboard
•
Pointing devices Mouse Trackball
•
Gaming devices Joystick Gamepad Game controller
•
Image, Video input devices Image scanner Webcam
•
Audio input devices Microphone
Output or Output devices •
Image, Video output devices Printer Peripheral device that produces a hard copy. (Inkjet, Laser) Monitor Device that takes signals and displays them. (CRT, LCD)
•
Audio output devices Speakers A device that converts analog audio signals into the equivalent air vibrations in order to make audible sound. Headset A device similar in functionality to computer speakers used mainly to not disturb others nearby.
The generic generic term term for for computer computer programs programs is ‘software’. ‘software’. Software Software comes comes in in two main types – system software and application programs. System software consists of programs that control the operations of the computer system itself. It consists of a group of programs that control the operations of a computer equipment including functions like managing memory, managing peripherals, loading, storing, and is an interface between the application programs and the computer. MS DOS (Microsoft’s Disk Operating S ystem), UNIX are examples of system software. Software that can perform a specific task for the user, such as word processing, accounting, budgeting or payroll, fall under the category of application software. Such programs run on top of an operating system (like Windows, UNIX, Linux, Macintosh) and are used to carry out specific functions. Word processors,
spreadsheets, database management systems are all examples of general purpose application programs. < TOP >
2.
a.
Drawing Objects in MS PowerPoint Objects can be text characters, images, charts, or any other similar element in MS PowerPoint. While the same technique can be used to create all objects, some objects can be enhanced with resizing, rotating/flipping, 3-D, shading, for example. These enhancements may not apply to all objects. Most objects can also simply be layered, duplicated, or grouped Drawing Objects
b.
1.
On the Drawing toolbar, click the AutoShapes menu button.
2.
Point to one of the 7 categories, and and then point to a shape. For example, point to Basic Shapes and then point to the Sun.
3.
Click the shape selected. Click the Sun button.
4.
The pointer changes to a cross-hair pointer.
5.
Position the pointer in the location where the object should appear – do not not click. click.
6.
Press and hold on the keyboard while while clicking clicking and dragging the pointer pointer to create the object. object.
7.
The shape shape will will appear appear with with white white squares squares on on each corner and side side of the object.
Modifying Objects in MS PowerPoint Selecting Objects Resizing. Copying, moving, deleting are all editing commands that can be performed on objects. Before an edits can be performed, the object must be selected. Select and Deselect objects: 1.
Click the object.
2.
To select select multiple multiple objects, hold down the key and select all objects needed.
3.
To deselect deselect objects, hold down the key and select select all all objects objects not needed.
Resize objects Many times an object will be drawn on a slide that does not fit. In other cases, the object may need to be moved to another position on the slide. Resize 1.
Click the object object to select select it. In the picture picture (below) the Sun Sun is selected.
2.
Place the the pointer over one of the resizing handles, the pointer will change change to a double-headed double-headed arrow.
3.
Click and drag the the pointer pointer in in the the direction direction the object object is to be resized to.
4.
Release the mouse.
Layering Objects When creating a Presentation, it may be necessary to layer objects on top of each other. However, the first object drawn is on the bottom of the slide and the last object drawn is on the top. To make adjustments, use the Order function on the Drawing toolbar. 1.
Select the object to be reordered
2.
On the the Drawing toolbar, click the Draw Draw button, button, select select Order Order and then select Send to Back. Back.
3.
The objects are now reordered.
Grouping Objects Grouping objects in MS PowerPoint makes it easier to edit and move information within a presentation. Instead of moving several objects at different times, the objects can be grouped and then they can all be moved at one time! 1.
Select the objects to be included in one group.
On the Drawing toolbar, click the Draw button, and then select Group. Ungrouping Objects 1.
Select the group by clicking on one of the group’s objects
2.
On the Drawing toolbar, from the
menu select Ungroup.
Regrouping Objects 1.
On the Drawing toolbar, from the
menu, select Regroup. The handles reappear around the most
recently ungrouped group. c.
Inserting ClipArt we can add pictures to your slides using those available with ClipArt. 1.
Select the slide on which you wish to add a picture.
2.
Select Insert -> Picture -> ClipArt from the menu.
3.
Right panel displaying options options to select the the Clip Organizer is displayed. displayed. Click on the Clip Organizer Organizer as shown.
4.
Select the category to select a picture from.
5.
Select the desired picture. Right Right click and use the copy and paste function to to paste it on the selected selected slide (optionally, you can drag the picture on the desired slide).
6.
You can then move move the picture to the desired desired location on the the slide slide (if (if required). required). < TOP >
3.
a.
A spreadsheet spreadsheet is the computer equivalent of a paper ledger ledger sheet. It consists of a grid made of columns columns and rows. It is an environment that can make number manipulations manipulations easy and straightforward. Microsoft (MS) Excel is a spreadsheet application that is part of Microsoft Office. It enables the calculation and display of complex mathematical formulas (functions) with a facility for extensive formatting. Functions are predefined calculations that may be included in any given Excel cell to perform specific manipulation of data. Using MS Excel, data could be imported from a variety of sources. Analyzing data is a very important skill of any professional, especially those who work in the fields of agriculture and natural resources where data in its raw collected state have very little use without some sort of processing. As a student and a professional, MS Excel can assist you in the analysis analysis of data. This tutorial focuses on introducing introducing the basic features of MS Excel 2003 to analyze general data. It will cover the basic steps of creating a spreadsheet, using formulas formulas and basic formatting, and creating charts. Creating a Worksheet To insert a new worksheet, follow the following steps:
b.
1.
Start MS Excel. The application starts with several worksheets (usually 3).
2.
To insert a new worksheet, click "Worksheet" from the "Insert" menu.
3.
Right-click on the tab for the the new worksheet and select select "Rename" from the the shortcut shortcut menu (alternatively, you could double-click the tab to accomplish the same).
4.
Type in "Grade Book" and press "Enter" to save the change.
5.
Key in the text and data data into into the worksheet as shown in the picture below. You will will notice notice that that your data is displayed in two areas while you you are typing it in a cell. Text is displayed in the active cell within the workbook and it is also displayed in the "Formula Bar". The "Formula Bar" is activated as soon as you begin typing in a cell. At the far left of the "Formula Bar" is the reference reference section, which will show the reference of the active cell.
6.
To change change the width of any column, column, position position the the pointer between the column column headings headings for two columns columns (the pointer should change shape to show a double-headed arrow as you position the pointer between the two column headings). When the pointer changes shape, you can change the width of the column by pressing the left mouse button and dragging to the right or left. Press the left mouse button and drag to the right until the width of the column fits the text.
7.
Once you have all the the data in, save your work by by clicking clicking "Save" from from the the "File" "File" menu. menu. Alternatively, you could click on the "Save" button on the toolbar. Given that this the first time you are attempting attempting to save a new workbook, MS Excel will display the "Save As" dialog and will prompt you to enter the file name for your new workbook. You also have many other choices including the choice of file folder where your workbook ought to be saved. Give your file a descriptive descriptive name before pressing "Save".
Formatting Your Worksheet Several formatting features features are available within MS Excel to effectively display your data. Text and individual characters can be formatted to make them stand out (you can format all of the text in a cell or only selected characters). characters). You may also rotate text (in a column for example) as well as add borders, colors, and patterns to distinguish distinguish among different types of of information in a worksheet. Also, you can use number formats to change the appearance of numbers, including dates and times, without changing the number behind the appearance. Finally, you can format cells and lists lists quickly using auto-formats, auto-formats, styles, and the "Format Painter" button. To demonstrate how to go about auto-formatting a worksheet, please follow the following steps: 1.
Select all the cells that that encompass encompass your title (i.e., (i.e., "A1") and click the down arrow to the right right of the
"Fill Color" button. Select the desired color. 2.
Select your grade book by clicking and holding in cell "A3" and dragging to cell "H10" and releasing.
3.
Select "AutoFormat" from the "Format" "Format" menu and select select the desired desired format from those provided provided and click "OK".
4.
In cell "C10" type "Average".
5.
Format cells D10 to H10 by first selecting these cells. On the "Format" menu, click "Cells", and and then then click the "Number" tab. In the Category list, click "Number" and leave the default default of two decimal places.
6.
c.
Save your work by clicking "Save" from from the "File" menu. Alternatively, you may click click on the the "Save" "Save" button on the toolbar to accomplish the same result. The Operands and Operators in MS-EXCEL The values we have used so far were provided in cells of a spreadsheet. In some cases, you will need to display a value that is a combination of other values. An operation is a technique of using a value or the contents of a cell, or to combine two or more values or contents of cells to either modify an existing value or to produce a new value. Based on this, to perform an operation, you need at least one value or the contents of one cell and one symbol. A value involved in an operation is called an operand. A symbol involved in an operation is called an operator. Regular Operators The Assignment Operator = In order to display a value in a cell, it must be preceded with the assignment operator, which is “=”. The syntax you would use is: =ValueOrExpression
The operand on the right side of the assignment operator is referred to as the right value or Rvalue. It can be a known value or a reference to another cell. There are two main ways we will use the assignment operator: •
Imagine you already have a cell such as B12 and you want to display its value in another cell such as A4. In A4, you can type =B12 and press Enter. The contents of B12 would be provided to, and displayed in, A4
In some other operations and functions we will learn, you can use the = operator inside of the expression or function to perform another, intermediary operation, such as a comparison . Unary Operators A unary operator is one that uses only one operand. An operator is referred to as binary if it operates on two operands. The Positive Unary Operator + Algebra uses a type of ruler to classify numbers. This fictitious ruler has a middle position of zero. The numbers on the left side of the 0 are considered negative while the numbers on the right side of the 0 constant are considered positive: A value on the right side of 0 is considered positive. To express that a number is positive, you can write a + sign to its left. The Negative Unary Operator If we want to negate the value of a cell, an expression, or a function, you can type the – operator on its left. The Double Quotes: "" Double-quotes are used to enclose a string. As we reviewed earlier, a string can be an empty space, one character, or a group of characters. Such a string must be considered “as is”. Therefore, to include a string in an expression, put it in double-quotes. To display a string in a cell, precede it with double-quotes. For example, to display Rancho Cordova in cell B4, you would click B4, type ="Rancho Cordova" and press Enter. The String Concatenator: & The & operator is used to append two strings, the contents of two cells, or expressions. This is considered as concatenating them. For example, it could allow you to concatenate a first name and a last name, producing a full name. The general syntax of the concatenation operator is expressed as: Value1 & Value2 •
To display a concatenated expression, use the assignment operator on the left of the string. For example, imagine you want to concatenate Juan to Marcus and display the resulting string in cell C5, in C5, you would
type =”Juan” & “Markus” and press Enter. The result would be JuanMarkus. To concatenate more than two expressions, you can use as many & operators between any two expressions as necessary. For example, to add an empty space in the above string, in cell C5, you would type =”Juan” & “ “ & “Markus” In the same way, you can concatenate the contents of various cells. The Addition: + The addition is used to add one value or expression to another. It is performed using the + symbol and its syntax is: Value1 + Value2 The addition allows you to add two numbers such as 12 + 548 or 5004.25 + 7.63 After performing the addition, you get a result. You can display such a result in a cell or use it as an intermediary variable in an expression. For example, to add 242.48 to 95.05 and display the result in cell C6, in C6, you would type =242.48 + 95. 05 and press Enter. The Subtraction: The subtraction is performed by retrieving one value from another value. This is done using the - symbol. The syntax used is: Value1 - Value2 The value of Value1 is subtracted from the value of Value2. After performing the operation, a new value results. This result can be used in any way you want. For example, you can display it in a cell using the assignment operator as follows: = Value1 - Value2 The Multiplication: * The multiplication allows adding one value to itself a certain number of times, set by the second value. The multiplication multiplication is performed with the * sign which is typed with Shift + 8. Here is an example: Value1 * Value2 During the operation, Value1 is repeatedly added to itself, Value2 times. The result can be assigned to another value or displayed in a control as follows: = Value1 * Value2 The Division: / The division is used to get the fraction of one number in terms of another. For example, to divide a Value1 if Value2 pieces, you would use a syntax as: Value1 / Value2 After performing the operation, you get a new result you can use as you see fit. You can display in a cell or involve it in an expression. The Exponentiation: ^ Exponentiation is the ability to raise a number to the power of another number. This operation is performed using the ^ operator (Shift + 6). It uses the following mathematical formula: yx The operation is performed as y^x and means the same thing. Either or both y and x can be values or expressions, but they must carry valid values that can be evaluated.When the operation is performed, the value of y is raised to the power of x. You can display the result of such an operation in a cell using the assignment operator as follows: =y^x You can also use the operation in an expression. The Parentheses Operators: () Parentheses are used to create sections in an expression. This regularly occurs when more than one operator is used in an operation. Parentheses allow you to specify which operation should be performed first in a multi-operator multi-operator operation. < TOP >
4.
a.
CREATING TABLES IN MS-WORD Creating the initial table 1.
Open your document
2.
Go to the page where you want the table
3.
Make sure your TABLES & BORDERS TOOLBAR is on. •
GO to VIEW, then TOOLBARS, then click on TABLES & BORDERS
4.
Look for the top line’s table icon (just left of the EXCEL icon) icon)
5.
Click on it and drag down and to the right right to get the number of rows and columns columns you need •
This results in a basic table looking like this:
Organizing your data in tables Left column should contain the primary thing you are describing in the table. •
Other columns contain the descriptive data
•
The top row contains your column “headers” – descriptions of what is in the column.
•
b.
You can think of it as being similar to EXCEL or other spreadsheets – each row is a “case” and each column contains a “variable” or data that describes that case.
Basic Formatting of Tables: Width of Columns: There are three options – a.
Drag the the column’s left or or right edge to where you want it (place pointer pointer over over edge, click and drag);
b.
Put the cursor in the column column you want to adjust and click on the TABLE command and then the AUTOFIT and AUTO FIT TO CONTENTS command. This fits the table columns to your text. Note that this is not always the best option.
c.
Put the cursor in the column column you want to adjust and and click on the TABLE command and then the TABLE PROPERTIES command and then the COLUMN tab and then type in the PREFERRED WIDTH.
Width of rows: Similar approach as columns. columns. Note that the default is to make the row row automatically the width needed for the text. However, you may wish wish to have all rows to have the same height. To do that, go to TABLE, AUTOFIT, then DISTRIBUTE ROWS EVENLY. You may find that it looks good to to have a bit of space between the text and the row’s top and bottom. The easiest way to deal with that is to highlight the the text and go to FORMAT; PARAGRAPH and add SPACING of 3 points in the BEFORE and AFTER boxes. Formatting the text within the table: •
All text is Times New Roman 10 point
•
The “header” row should be bold text.
•
The left column (the primary focus of the table) should be bold.
•
If there is a bottom “total” row, it should be bold text.
•
The remaining cells of the table should be regular text.
Justifying the text within the table •
You can do most justification using the justification button, which is located four to the left of the AZ down arrow sort button. This gives you nine choices (left, centered, centered, right justify combined with top, centered, and bottom justify).
•
The header row is usually centered both left to right and top to bottom (except left column header, which is left and top/bottom centered).
• •
Left column should be left and top/bottom centered justified. justified. Numerical data is usually usually centered in both directions. directions. However, this only looks good when all the data cells in the column have the same same number of digits in them. If this is not the case, it works better better to right-justify the numbers and then use the paragraph command to right indent them so that they fall approx in the center of the column. An easier alternative for right indenting indenting is to use the ruler (if not already on, you can turn it on by going to VIEW and clicking on the ruler ruler command. Now highlight cells that need to be right indented and move the little wall-tent shaped thing in the ruler to a place
where it is just to the right of the center. •
Text is usually left-justified. left-justified. Column headers for text should also be left justified
Adding borders to the table •
The default is to have regular lines lines in the interior and exterior exterior of the table. This needs to be spruced up.
•
Highlight the Header row. Assign the top of that row a thick line using using the line tool (two to the right of the little pencil on the toolbar) and the line placement tool (immediately to the right of the little pencil that floats over a thick line). line). I prefer to use the thick line line with thin line under it combo for the the top border. Make the bottom border of the header row a double line.
•
Put a double line on the top of your Total row at the bottom if you have one.
•
The bottom line of the table should be a thick line with a thin line above combo.
•
Interior lines may or may not be needed depending on how big the table is and what it looks like.
•
•
c.
If you have many items in the left column, it is a good idea to break them up some how so the reader can follow them across the data. There are two common ways to deal with this: (1) after every third item, have an empty row; or (2) after every third item, make the bottom of that row have a closely dashed line going across the entire row. The left and right exterior borders should be a regular line.
AutoFormat of tables 1.
Highlight the table by clicking clicking on on the table marker(upper left corner of table). table).
2.
Click on the Table menu
3.
Click on Table AutoFormat
4.
Click on the Table style desired
5.
Click on any Apply special format options appropriate
6.
Click Apply button. < TOP >
Section B 5.
Threats to Computer Security Computer systems are vulnerable to many threats that can inflict various types of damage resulting in significant losses. This damage can range from errors harming database integrity to fires destroying entire computer centers. Losses can stem, for example, from the actions of supposedly trusted employees defrauding a system, from outside hackers, or from careless data entry clerks. Precision in estimating computer security-related losses is not possible because many losses are never discovered, and others are "swept under the carpet" to avoid unfavorable publicity. The effects of various threats varies considerably: some affect the confidentiality or integrity of data while others affect the availability of a system. a.
b.
Errors and Omissions Errors and omissions are an important threat to data and system integrity. These errors are caused not only by data entry clerks processing hundreds of transactions per day, but also by all types of users who create and edit data. Many programs, especially those designed by users for personal computers, lack quality control measures. However, even the most sophisticated programs cannot detect all types of input errors or omissions. A sound awareness and training program can help an organization reduce the number and severity of errors and omissions. Users, data entry clerks, system operators, and programmers frequently make errors that contribute directly or indirectly to security problems. In some cases, the error is the threat, such as a data entry error or a programming error that crashes a system. In other cases, the errors create vulnerabilities. Errors can occur during all phases of the systems life cycle. Fraud and Theft Computer systems can be exploited for both fraud and theft both by "automating" traditional methods of fraud and by using new methods. For example, individuals may use a computer to skim small amounts of money from a large number of financial accounts, assuming that small discrepancies may not be investigated. Financial systems are not the only ones at risk. Systems that control access to any resource are targets (e.g., time and attendance systems, inventory systems, school grading systems, and long-distance telephone systems). Computer fraud and theft can be committed by insiders or outsiders. Insiders (i.e., authorized users of a system) are responsible for the majority of fraud. Since insiders have both access to and familiarity with the victim computer system (including what resources
it controls and its flaws), authorized system users are in a better position to commit crimes. Insiders can be both general users (such as clerks) or technical staff members. An organization's former employees, with their knowledge of an organization's operations, may also pose a threat, particularly if their access is not terminated promptly. c.
Employee Sabotage Employees are most familiar with their employer's computers and applications, including knowing what actions might cause the most damage, mischief, or sabotage. The downsizing of organizations in both the public and private sectors has created a group of individuals with organizational knowledge, who may retain potential system access (e.g., if system accounts are not deleted in a timely manner). The number of incidents of employee sabotage is believed to be much smaller than the instances of theft, but the cost of such incidents can be quite high. Common examples of computer-related employee sabotage include:
d.
•
destroying hardware or facilities,
•
planting logic bombs that destroy
•
programs or data,
•
entering data incorrectly,
•
"crashing" systems,
•
deleting data,
•
holding data hostage, and
•
changing data.
Loss of Physical and Infrastructure Support The loss of supporting infrastructure includes power failures (outages, spikes, and brownouts), loss of communications, water outages and leaks, sewer problems, lack of transportation services, fire, flood, civil unrest, and strikes.
e.
Malicious Hackers The term malicious hackers, sometimes called crackers, refers to those who break into computers without authorization. They can include both outsiders and insiders. Much of the rise of hacker activity is often attributed to increases in connectivity in both government and industry. One 1992 study of a particular Internet site (i.e., one computer system) found that hackers attempted to break in at least once every other day. The hacker threat should be considered in terms of past and potential future damage. Although current losses due to hacker attacks are significantly smaller than losses due to insider theft and sabotage, the hacker problem is widespread and serious.
f.
Industrial Espionage Industrial espionage is the act of gathering proprietary data from private companies or the government for the purpose of aiding another company(ies). Industrial espionage can be perpetrated either by companies seeking to improve their competitive advantage or by governments seeking to aid their domestic industries. Foreign industrial espionage carried out by a government is often referred to as economic espionage. Since information is processed and stored on computer systems, computer security can help protect against such threats; it can do little, however, to reduce the threat of authorized employees selling that information.
g.
Malicious Code Malicious code refers to viruses, worms, Trojan horses, logic bombs, and other "uninvited" software. Sometimes mistakenly associated only with personal computers, malicious code can attack other platforms. Actual costs attributed to the presence of malicious code have resulted primarily from system outages and staff time involved in repairing the systems. Nonetheless, these costs can be significant. Malicious Software: A Few Key Terms Virus: Virus : A code segment that replicates by attaching copies of itself to existing executables. The new copy of the virus is executed when a user executes the new host program. The virus may include an additional "payload" that triggers when specific conditions are met. For example, some viruses display a text string on a particular date. There are many types of viruses, including variants, overwriting, resident, stealth, and polymorphic. Trojan Horse: Horse: A program that performs a desired task, but that also includes unexpected (and undesirable) functions. Consider as an example an editing program for a multiuser system. This program could be modified to randomly delete one of the users' files each time they perform a useful function (editing), but the deletions are unexpected and definitely undesired.
Worm: Worm: A self-replicating program that is self-contained and does not require a host program. The program creates a copy of itself and causes it to execute; no user intervention is required. Worms commonly use network services to propagate to other host systems. h.
Threats to Personal Privacy The accumulation of vast amounts of electronic information about individuals by governments, credit bureaus, and private companies, combined with the ability of computers to monitor, process, and aggregate large amounts of information about individuals have created a threat to individual privacy. < TOP >
6.
The key elements of a Windows desktop include : •
Icons, and
•
Taskbar
Icons Icons are labeled pictures and represent applications that can be loaded into the computer’s memory. Typically, these can be classified into four types. Program Icon When double clicked, it loads the corresponding application in the computer’s memory and runs the application in a windows. Shortcut Icon These provide an alternate way to open programs, folders and documents. These icons are characterized by a small curved arrow on the lower left hand corner and their labels generally begin with ‘Shortcut to’. Deleting such an icon does not delete the actual associated program, but deletes only the shortcut pointing to it. Folder Icons When double clicked, they open the respective folder and display the contents of the folder. System Icons Are mandatory programs or files located on the desktop. Users are not allowed to delete system icons. ‘Recycle Bin’, ‘My Computer’, and ‘Network Neighborhood’ are all examples of system icons. Taskbar The Windows Taskbar is located at the bottom of the desktop and comprises several elements – Start Button, Quick Launch, and the System Tray. Start Button This provides access to the ‘Start Menu’. All applications and tools available in the computer can be accessed from this menu. It may be of interest to know that the form, in which the menu is displayed on clicking the start button, is customizable. Quick Launch It allows for an immediate access to a variety of elements. By clicking on the icon, the associated program or Windows tool is launched. Icons for different programs can be added to t he quick launch toolbar. System Tray It displays the applications that are currently running (active/background). It also includes a clock (on the extreme right) that displays the current time and can b e set by the user. < TOP >
7.
A pivot table is a powerful data summarization tool found in spreadsheet programs. Among other functions, it can automatically sort, count, and total data stored in a spreadsheet and create a second table displaying the summarized data. Pivot tables are useful to quickly create crosstabs. The user sets up and changes the summary's structure by dragging-and-dropping fields graphically. This "rotation" or pivoting of the summary table gives the concept its name. Uses of a pivot table : •
Pivot tables are easy to rearrange
•
Pivot tables provide a way to look for trends
•
Pivot tables will impress your colleagues
•
Pivot tables are under-utilized
•
Pivot tables are simple to learn
Explanation of a pivot table
For typical data entry and storage, d ata is usually flat. Flat means that it consists of only columns and rows. While there is a lot of information stored in such data, it is very difficult to gather the information you want out of it. A pivot table can help you quickly summarize the flat data, giving it depth, and get the information you want. The usage of a pivot table is extremely broad and depends on the situation. A pivot table usually consists of row, column, and data(or fact) fields. In this case, the row is Region, the column is Ship Date, and the data we would like to see is Units. These fields were dragged onto the pivot table from a list of available fields. Pivot tables also allow several kinds of aggregations including: sum, average, standard deviation, Count, etc. In this case, we wanted to see the total number of units shipped, so we used a sum aggregation. Build a pivot table in 6 steps: 1.
Select your data source.
2.
Choose “pivot table” in data menu.
3.
Specify your data range.
4.
Choose to put results on a new sheet.
5.
Click “layout” button and drag fields to the the pivot pivot table table dimensions dimensions where you you want them to appear.
Click on “okay” and “finish”. < TOP >
Section C 8.
Windows Explorer Information in your computer is saved as a file. A file is defined as a collection of related information or records. Files can be grouped and placed under directories. Grouping of files in directories and sub-directories provides an order to the information placed on your computer. It is much like the files stored in cabinets to classify and group them for easy access. Comparing these, we could say that the cabinet drawers can be related to the directories and sub-directories, sub-directories, and the physical files can be related to the computer files stored in these directories. Windows terms directories and sub-directories as F olders and Sub-folders. The folder structure of Windows can be understood as an inverted tree with the root being at the top having folders, sub-folders and files under it – the number of folders and files limited only by the disk capacity. Represented diagrammatically diagrammatically it would look something like this :
The Windows Explorer is a utility that allows you to perform various disk and file management activities like creating folder(s), creating, copying, renaming and deleting file(s) etc. It represents the contents in a graphical form giving an easy and quick view of your computer contents. Steps to Access the Windows Explorer Select Start -> All Programs -> Accessories -> Windows Explorer This will start the Explorer and display the following screen : Tree View Windows Explorer displays all items in a tree structure. A plus sign (+) next to an item indicates that it can be expanded further (like in case of a folder), and a minus sign ( −) indicates that it is the expanded view. You can click on the plus sign to reveal or expand the contents of the item. Items that neither have a plus or a minus sign
indicate that they are the lowest level in the tree hierarchy. Standard Toolbar It is the toolbar that provide access to the most commonly used functions. Selected Item The item that has the current focus (usually highlighted in blue). Address Bar Displays the path of the selected item. This item could be a file, folder, or the drive itself. Left/Right Pane The explorer Window is divided into two panes – left and right. The left pane is used to select a drive or folder, the contents of which are displayed in the right pane. Creating Folders Steps to Create a New Folder 1.
Select the drive, drive, e.g. ‘C’ (or (or folder folder in case you are creating creating a sub-folder) in Windows Windows Explorer Explorer under which you wish to create the new folder. This can be done by clicking once on the drive name.
2.
From the File File menu, menu, point to New and click on Folder. Folder. A new folder folder appears appears with a temporary temporary name name ‘New ‘New Folder’ in the selected location.
3.
Type the name for the new folder, and press Enter. It may be useful to know that folder/file names can be up to255 characters, including spaces. These, however, cannot contain the following characters :
/
\
:
,
*
?
‘
“
<
>
|
Thus, it is advisable to keep the names simple and w ithout any special character. Alternatively, you can also initiate the New -> Folder menu by right clicking in the right pane of Windows Explorer. The screen that appears on doing the same is shown below. Opening Files/Folders Files or Folders can be opened by double clicking on the same. Opening a Folder simply means displaying the contents of the folder (its sub-folders and files). As a general rule, the file opens with the application it was created and the extension of the file name is an indication of the application, for example, January.xls indicates that the file is an Excel file. Steps to Open a File/Folder 1.
Select the desired file (or folder) from Windows Explorer; and
2.
Double click on the file (or folder) to open it.
Copying Files Files and/or folders can be copied using the ‘Click and Drag’ method. Steps to Copy a File/Folder 1. 2.
Click on the file (or folder) you want to move to another location. Keep the the mouse button pressed pressed on the highlighted file, drag drag it to the folder you want to drag drag it to, and then release the mouse button.
You will notice that using this method, if you drag the file (or folder) to the same disk, it will result in moving it while if you drag it to another disk it will be copied. To copy a file using Click and Drag from one folder to another on the same disk, select the desired file, drag the file using the right mouse button and when you reach the desired location simply right click and select Copy here option. You can copy more than one file in a single copy operation. These files could be displayed in continuation or scattered across the folder (discontinuous). Described below is how to handle each of these situations. Continuous Range You can select a continuous range of files as follows : 1. 2. 3.
Click on the first file in the range; Press down the Shift key and while holding holding down the shift shift key click on the last file file in the range. range. The selected range will now be highlighted; and You can now cut and copy them in in another location or use the Click Click and Drag method method to do the same.
Separate Files
You can select a discontinuous range of files as follows : 1. 2.
Click on the first file you want to copy; and Hold down the Ctrl Ctrl key and while doing so click on another file. You can select select more files in in the same manner.
Renaming Files/Folders Renaming a file (or folder) is assigning a new name to it. The steps below detail how this can be done. Steps to Rename a File/Folder 1. 2. 3.
Select the desired file (or folder) from Windows Explorer; From the File File menu menu click click on Rename. The focus moves moves to to the earlier highlighted file (or (or folder) folder) whose name is to be changed; and Type the desired name and press Enter.
Deleting Files/Folders Deleting a File (or folder) moves it to the Recycle Bin. Follow the steps below to delete : Steps to Delete a File/Folder 1.
Select the desired file (or folder) from Windows Explorer;
2.
From the File File menu menu click click on Delete. This displays a dialogue dialogue box box asking asking for confirmation to delete; delete; and
3.
Select ‘Yes’ from the dialogue dialogue box to to confirm confirm or select select ‘No’ ‘No’ in case you change change your mind.
Changing Folder Views The files/folders in the Windows Explorer can be displayed using different view forms. You can choose the one that suits you the most. Steps to Change the Folder Views Select the View menu. Various display options are available to select from. These include Thumbnails, Tile, Icon, List and Details. Each of these is shown below. Thumbnails In this view, each file or folder is displayed as a thumbnail with the name underneath. Tile Files and folders are tiled with the name and details displayed to their right. Icon In this view, each file or folder is shown as a small icon with the name or description below it. The items are arranged horizontally in this view. List This is a view analogous to the Icon view but the icons are arranged vertically rather than horizontally. Details This is the default view. It provides details like the item name, size, type and date modified. You can change the size of column widths by dragging the borders (left, right) between the column headings. You can also sort (ascending, descending) the display based on any of these columns by clicking on the corresponding heading. < TOP >
9.
Creating a Macro in MS-WORD •
Open a new Word document
•
Type in a few words of text. A nything you like
•
Highlight your text, or just a single word of the text
•
From the menu bar, click on Tools
•
From the drop down menu click on Macro
•
A sub menu appears
•
Click on Record New Macro .When you click on Record New Macro, you get the Macro dialogue box popping up.
There are four areas to the Record Macro dialogue box: Macro Name, Assign macro to, Store macro in, and Description. The first thing to do is to give your macro a name. At the moment it is called "Macro1". That's not a very descriptive name for what we want our macro to do. We'll call our macro FontChanger. Notice that we haven't put
a space between the two words. This is because macros don't like having spaces between words. You have to put the name of your macro as all one word. So go ahead and type in FontChanger as the Macro name, instead of Macro1. The next section is "Assign macro to". You are given the choice of either Toolbars or Keyboard. Ignore this section for now. We'll see later how to assign our macro to a toolbar, and to the keyboard. The next section is "Store macro in". At the moment it reads All Documents (Normal.dot). Remember what Normal.dot is? That's the basic template for all Microsoft Word documents. In other words, the macro we create will be available to any new Word document. You can change this so that the macro is created in only the document you're working on. Click the black down arrow to see the title of the document you have open. The final section is Description. This is just a record of when the macro was created, and who created it. You can change this to anything you like. Malicious folk creating nasty macros will definitely change these details. Once you have given your macro a name, click the OK button. a dialogue box will appear. When you click the OK button, you are returned to your Word document. But now you will see a strange toolbar floating over your page. And the mouse pointer will be different. •
Click on Format from the menu bar
•
From the drop down menu, click on Font
•
The Font dialogue box appears
•
Select Arial as your font
•
Select Bold
•
Select size 16
•
Click the OK button on the Font dialogue box
•
You are returned to your page
•
Click the Stop button on your floating Macro Recorder
•
The macro will stop recording, and the process is finished: You have recorded the macro. < TOP >
10.
Cryptanalysis and Attacks on Cryptosystems Cryptanalysis is the art of deciphering encrypted communications without knowing the proper keys. There are many cryptanalytic techniques. Some of the more important ones for a system implementor are described below. : This is the situation where the attacker does not know anything about the contents of the message, and must work from ciphertext only. In practice it is quite often possible to make guesses about the plaintext, as many types of messages have fixed format headers. Even ordinary letters and documents begin in a very predictable way. For example, many classical attacks use frequency analysis of the ciphertext, however, this does not work well against modern ciphers. Modern cryptosystems are not weak against ciphertext-only attacks, although sometimes they are considered with the added assumption that the message contains some statistical bias. Known-plaintext attack: The attacker knows or can guess the plaintext for some parts of the ciphertext. The task is to decrypt the rest of the ciphertext blocks using this information. This may be done by determining the key used to encrypt the data, or via some shortcut. One of the best known modern known-plaintext attacks is linear cryptanalysis against block ciphers. : The attacker is able to have any text he likes encrypted with the unknown key. The task is to determine the key used for encryption. A good example of this attack is the differential cryptanalysis which can be applied against block ciphers and in some cases also against hash functions. Some cryptosystems, particularly RSA, are vulnerable to chosen-plaintext attacks. When such algorithms are used, care must be taken to design the application or protocol so that an attacker can never have chosen plaintext encrypted. Man-in-the-middle Man-in-the-middle attack: This attack is relevant for cryptographic communication and key exchange protocols. The idea is that when two parties, A and B, are exchanging keys for secure communication, an adversary positions himself between A and B on the communication line. The adversary then intercepts the signals that A and B send to each other, and performs a key exchange with A and B separately. A and B will end up using a different key, each of which is known to the adversary. The adversary can then decrypt any communication from A with the key he shares with A, and then resends the communication to B by encrypting it again with the key he shares with B. Both A and B will think that they are communicating securely, but in fact the adversary is hearing everything.
The usual way to prevent the man-in-the-middle attack is to use a public-key cryptosystem capable of providing digital signatures. For set up, the parties must know each other's public keys in advance. After the shared secret has been generated, the parties send digital signatures of it to each other. The man-in-the-middle man-in-the-middle fails in his attack, because he is unable to forge these signatures without the knowledge of the private keys used for s igning. This solution is sufficient if there also exists a way to securely distribute public keys. One such way is a certification certification hierarchy such as X. 509. It is used for example in IPSec. Correlation Correlation between the secret key and the output of the cryptosystem is the main source of information to the cryptanalyst. In the easiest case, the information about the secret key is directly leaked by the cryptosystem. More complicated cases require studying the correlation (basically, any relation that would not be expected on the basis of chance alone) between the observed (or measured) information about the cryptosystem and the guessed key information. Attack against or using the underlying hardware: hardware : in the last few years as more and more small mobile crypto devices have come into widespread use, a new category of attacks has become relevant which aims directly at the hardware implementation of the cryptosystem. The attacks use the data from very fine measurements of the crypto device doing, say, encryption and compute key information from these measurements. The basic ideas are then closely related to those in other correlation attacks. For instance, the attacker guesses some key bits and attempts to verify the correctness of the guess by studying correlation against her measurements. Several attacks have been proposed such as using careful timings of the device, fine measurements of the power consumption, and radiation patterns. These measurements can be used to obtain the secret key or other kinds information stored on the device. This attack is generally independent of the used cryptographical algorithms and can be applied to any device that is not explicitly protected against it. Faults in cryptosystems can lead to cryptanalysis and even the discovery of the secret key. The interest in cryptographical devices lead to the discovery that some algorithms behaved very badly with the introduction of small faults in the internal computation. For example, the usual implementation of RSA private-key operations are very suspectible to fault attacks. It has been shown that by causing one bit of error at a suitable point can reveal the factorization of the modulus i.e. it reveals the private key. Similar ideas have been applied to a wide range of algorithms and devices. It is thus necessary that cryptographical devices are designed to be highly resistant against faults and against malicious introduction of faults by cryptanalysts. < TOP >
11.
Managing Files and folders in Windows Almost all Windows 2000 tasks involve working with files and folders. The work you do with files and folders falls into three categories: Organizing and managing files and folders You can perform basic file and folder tasks, such as creating, deleting, copying, and moving files and folders, and more advanced tasks, such as changing file and folder properties and managing shared folders. Searching for files and folders You can narrow the focus of your file and folder searches by including additional search criteria, such as the date, type, file size, or case sensitivity. You can also broaden the scope of your file searches by using wildcard characters, and specifying literal text or regular expressions. Securing your files and folders You can secure files and folders using Windows 2000 Professional security features, such as user and group accounts, Group Policy, shared folder and printer permissions, auditing, and user rights. If you have an NTFS drive installed, you can set file and folder permissions and encrypt files and folders. To open a file or folder 1.
Open My Computer, and then double-click the drive that contains the file.
2.
Double-click the file or folder you want to open.
To save a file 1.
On the File menu of the program you are working in, click Save.
2.
If you haven't saved your file before, type a name for the file in File name.
To create a new folder 1.
Open Windows Explorer.
2.
Click the drive or folder in which you want to create a new folder.
3.
On the File menu, point to New, and then click Folder.
4.
Type a name for the new folder, and then press ENTER
To copy or move a file or folder 1.
Open Windows Explorer.
2.
Click the drive or folder you want to work with.
3.
Click the file or folder you want to copy or move.
4.
On the Edit menu, click Copy. Or, click Cut to move the item.
5.
Open the folder or disk where you want to copy or move the item.
6.
On the Edit menu, click Paste.
To copy a file or folder to a floppy disk 1.
Insert the floppy disk into the disk drive.
2.
Open Windows Explorer.
3.
Click the file or folder you want to copy.
4.
On the File menu, point to Send To, and then click 3 1/2 Floppy (A).
To delete a file or folder 1.
Open Windows Explorer
2.
Click the file or folder you want to delete.
3.
On the File menu, click Delete.
To delete or restore files in the Recycle Bin 1.
On the desktop, double-click Recycle Bin.
Do one of the following: To restore an item, right-click it, and t hen click Restore. To restore all of the items, on the Edit menu, click Select All, and then on the File menu, click Restore. To delete an item, right-click it, and then click Delete. To delete all of the items, on the File menu, click Empty Recycle Bin. To search for a file or folder 1.
Click Start, point to Search, and then click For Files or Folders.
2.
In Search Search for files or folders folders named, named, type all or part of the file file name or folder folder you want to find.
3.
To search search for files files containing specific text, in Containing Containing text, type the text you you want to find.
4.
In Look in, click the drive, folder, or network you want to search. To specify additional search criteria, click Search Options, and then click one or more of the following options to narrow your search: Select Date to look for files that were created or modified on or between specific dates Select Type to look for files of a specific type, such as a text or WordPad document. Select Size to look for files of a specific size. Select Advanced Options to specify additional search criteria.
5.
Click Search Now. < TOP >
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