2.3.1 Defensive Design

• What is the purpose of input sanitisation in defensive design?

  To clean up input data and remove unwanted data
• How does verification help in defensive design?

  It checks whether data has been entered correctly by example
• What is authentication in the context of defensive design?

  Ensuring only authorized users can gain access to the system
• Which of the following is NOT a method of authentication?

  Visual check
• Why is maintainable code important in defensive design?

  It allows other programmers to understand the code
• What is validation in defensive design?

  Checking whether input data is sensible and follows criteria
• What is a check digit used for?

  To verify that a tracking code has been entered correctly
• What does a type check ensure?

  That the data inputted is of the correct data type
• What is a format check?

  A check to ensure data follows a set pattern
• What does a length check do?

  Limits the number of characters in input data
• What is the purpose of a lookup table in validation?

  To ensure the data inputted is from an allowed set of values
• What does a presence check verify?

  That data has been entered into a field
• What is a range check used for?

  To ensure input is within sensible limits
• What are the key components of maintainability in code?

  • Comments/annotations to explain functions
  • Indentation to show structure
  • Sensible variable naming for clarity
  • Modularization for reuse and testing
  • Using constants to prevent data changes
• What is the purpose of using constants in code?

  To ensure specific data isn't changed