Defensive design

Defensive design

1. Input sanitisation

   • Removes any unwanted character before passing data through the program.
   • Often done using a whitelist or blacklist

2. Validation

   • Checks if the data meets a certain criteria before passing into the program.
     • Example: checking if an email address contains an @ symbol.
   • Often done using a whitelist or blacklist
     • A whitelist is a list of data that the program should accept
     • A blacklist is a list of all of the data the program should reject.

3. Verification

   • Checks whether the data entered is correct
     • Example: makes you write your password twice.

4. Authentication

   • Only allows authorised users to gain access
     • Example: usernames and passwords, user access levels

5. Maintainable code

   • Allows other programmers to understand the code
     • Example: comments, indentation, meaningful variable names