Producing a Robust Program

Producing a Robust Program

1. Validation

   • Validation helps a programmer to ensure that any data input is possible and sensible. Validation applies rules to inputted data. If the data does not follow the rules, it is rejected, reducing the risk that incorrectly input data may crash a program.
     • A programmer can build various types of validation into a program: Range check - the input must fall within a specified range. This is usually applied to numbers and dates, but can apply to characters. For example, when making a payment to someone, the amount to be entered might be set to be greater than zero and not greater than the funds available. Length check - the input must not be too long or too short. For example, a surname will require at least one letter, but is unlikely to require more than 40. Presence check - a data value must be entered. For example, entering a quantity when placing an order. Format check - the data must be in the correct format, such as entering a date in the format DD/MM/YYYY. Type check - the data must be of a specified data type, such as an integer when specifying a quantity.

2. Data Sanitisation

   • The purpose of data sanitisation is to hide or protect data so it can’t be seen or disclosed. Data can be sanitised in several ways. One example of data sanitisation is known as masking. Masking hides visible data by replacing it with something else. A good example of this is when a person enters a password. On many systems, as the user types in their password, all that can be seen of the password is a series of asterisks or dots, one for each character typed in. Here, masking protects the user as the actual password is not visible to anyone who might be looking at the screen.
     • Another method of data sanitisation is input sanitisation. Input sanitisation checks data that is entered and removes anything that might be potentially dangerous. A good example of this is on a website form. A hacker might try to gain access to a website’s data through a SQL injection attack. This would involve the hacker entering an SQL command into a website form to try and take control of the form’s linked database. Input sanitisation could be used here to remove any SQL commands from the inputted data, preventing a hacker from gaining control of the database.

3. Authentication

   • Authentication is the process of a user confirming that they are who they say they are on a computer system. In a network, this is often done through inputting a username and password. For networks that require high levels of security, authentication may include other methods. The factors of authentication can be broken down into three main groups: something you are - username, bank account number, or anything that identifies the user uniquely something you know - password, pin, secret answer to a question something you have - swipe card, biometrics, any other physical identifying device

4. Maintainability

   • The purpose of maintainability is to ensure that, over time, a program can be easily maintained. A programmer may decide to return to a program they wrote some time before in order to add an extra feature. Additionally, another programmer may wish to modify the program in order to improve it or debug an error. In both situations, the understanding of the program, how it works and the purpose of the code will be made easier if the program is written in a maintainable style. This includes using comments, sensible variable names ad indentation.