Defensive Dsesign

Question 1

what is the purpose of defensive design

Answer 1

to ensure programs are functioning properly

Question 2

what will programmers try to do to protect their programs using defensive design

Answer 2

• anticipate how users might misuse the program then try to prevent it
• ensure their code is well maintained
• reduce the number of errors in the code through testing

Question 3

what is the easiest way for a user to intentionally or accidentally misuse program

Answer 3

through entering data

Question 4

what are the two ways you can prevent users from entering something you dont want them to

Answer 4

• input sanitisation

- input validation

Question 5

what is input sanitisation

Answer 5

removing any unwanted characters before passing the data through the program

Question 6

what is input validation

Answer 6

• checking data meets certain criteria before passing it through the program
• such as checking whether an email hasan @ symbol or a suitable ending like .com

Question 7

what are the different types of validation input checks you can use

Answer 7

• range check
• presence check
• check digit
• format check
• look up table
• length check

Question 8

what does a range check do

Answer 8

checks data is within a specified range

Question 9

what does a presence check do

Answer 9

checks the data has actually been entered

Question 10

what does a check digit do

Answer 10

checks numerical data has been entered successfully

Question 11

what does a format check do

Answer 11

checks the data has the correct format

Question 12

what does a look up table do

Answer 12

checks the data against table of acceptable values

Question 13

what does a length check do

Answer 13

checks the data is the correct length

Question 14

what does authentication do

Answer 14

• confirms the identity of the user
• before they are allowed to access eices of data or features of a program
• such as using passwords

Question 15

what ways are used to increase the securtiy of password authentication systems

Answer 15

• force users to make strong passwords and change it regularly
• limit the number of failed authentication attempts before access to the account is lost
• ask for a random selection of characters from the password on each authentication

Question 16

what are the disadvantages of being too over the top with authentication

Answer 16

• it may affects a programs functionality

- and put people off of using it