paper 2 Flashcards
what does cyber security mean
it is the processes, policies and practices designed to protect any threats or unauthorised access to networks, computer, programs or data
how can captcha improve the security
- tells human and computers apart by providing obcured words which computers arent able to recognise or detect = prevents bots from masquerading as humans
how can email confirmation improve the security
- used to send a code / link to an email address provided by user , if they click on the link in the email it authenticates them as the user of that email account
what is a foreign key
Let that references the primary key from another table
what is data inconsistency
when multiple copies of the same information are stored in more than one place at a time
what is a database
Way of holding data in organised way so that searching for data items that meet certain criteria is quick and easy
describe how viruses work
- program installed on computer without user’s knowledge / permission with purpose of doing harm - it includes instructions to replicate itself automatically on a computer and to other computers
describe how trojans work
- program that masquerades as having one legitimate purpose but actually has another purpose- normally spread by email
- user is invited to click on link for a purpose which then executes a program with may give controller unauthorised access to the computer
describe blagging
Art of creating a fake scenario in which a victim may feel it is appropriate to divulge information that would not give out under normal circumstances
describe phishing
Email redirects users to fake websites where the reader is tricked into divulging confidential information eg passwords that can be used for fraud
how does encryption make transmission of data more secure
Unexpected messages / dataset ( plaintext ) is converted to cipher text by encoding it using an encryption algorithm - the key and the algorithm are required to encode / decode data
how are SMTP used
Sends email messages between mail servers - but is only used for sending
how is IMAP used
- accesses emails on the mail server via multiple devices - it maintains synchronisation of an email account across all devices
what are advantages to networks
- sharing resources - folders and files can be stored on a file server so they can be accessed by authorised users from any computer on the network
- peripheral devices such as printers and scanners can be shared
- internet connection can be shared
- user profiles and security can all be managed centrally
- software can be distributed across network rather than installing in individual computers
- all files can be backed up on central servers
what are disadvantages of networks
- if file server is switched off or the connection is damaged your files and folders cannot be accessed
- faults may cause loss of data
- networks require constant administration and management to keep them running smoothly
- larger networks become larger to manage = expensive maintenance
- multiple computers connected to network so more susceptible to damage via viruses
what is a computer network
Several computers interconnected together
how do compilers operate
- translates a high level language program ( source code ) in one go to produce object code
-produces executable files so the original code does not need to be compiled again
- the compiled program executes faster as it is already in machine code
what are differences between high level programming and low level programming languages
High - has a syntax and structure similar to English and is designed to be understood by humans- low level baggage is machine language
debugging is easier for high level than low level
- low pevel requires assemblers for translating instructions - high level require compiler and interpreter
how can you improve the performance of a CPU
- increasing the number of crores the greater the number of instructions it can process in a given space of time. - a dual or quad processor will be able to perform 2/4 operations simultaneously
- increasing the clock speeds which will increase the number of fetch execute cycles per second
- The bigger its cache, the less time a processor has to wait for instructions to be fetched and transferred
describe the function of a control unit
Coordinates all of the CPU actions in the fetch decode execute cycle and decode’s instructions AND sends and receives control signals to fetch and write data
describe the function of a clock
Regulates the speed and timing of all signals and computer functions
How do operators operate
- translates and executes one line of a high level language program at a time
- takes more time to execute as each instruction is translated before it is executed
- original code will be interpreted or translated every time it is run
- the interpreter must be installed to run the program
- takes more time to execute as each instruction is translated before executed
