2.3 robust programs

2.3 robust programs

1. Producing robust programs so that they are defensive against hacks and attacks.

   • Data Validation: check to ensure that the data entered is sensible and reasonable. It does not check the accuracy of data.
   • Data Sanitisation: Trims or strips strings, removing unwanted characters to make sure it contains only permitted characters . E.g. Da%ve the % would be removed.
   • Authentication: The process of verifying the identify of a user or process
   • Maintainability : Updating code so that it is compatible with current requirements
   • Comments: To help describe the code and structures in a program using #
   • Indentation: used to show the programs structure e.g. where selection or iteration or functions are used .

2. Anticipating Misuse

   • Defensive program design will consider and anticipate misuse.
   • Many programs and systems only allow a user to enter a password three or four times before it locks out the system.

3. Contingency Planning:

   • Planning: Once a programmer has anticipated the misuse they can then plan for the these issues.
   • issues. For example: Limiting the number of logon attempts. Ensuring the code is robust in validating the data entered

4. Iterative testing: This happens overtime and is repeated throughout the development of the program

   • Final/terminal testing: is when the product is released and real end users begin using it. Very often, end users find things wrong with systems that the programmers did not expect.
   • Syntax Errors: An error in the rules/grammar of the language Eg missing colon / spelling mistake
   • Logic errors: The program is written to do something other than what the programmer intended Eg Resetting only the first 9 elements in an array instead of all 10.
   • Test Data: Something which has been specifically identified for use in tests, typically of a computer program