Authentication Routines (AQA GCSE Computer Science)

Authentication Routines

What is authentication?

• Authentication is the process of ensuring that a system is secure by asking the user to complete tasks to prove they are an authorised user of the system

• Authentication is done because bots can submit data in online forms

• Authentication can be done in several ways, these include

  • Usernames and Passwords

  • CAPTCHA

• Other methods that programmers can do to authenticate the user is include

  • Allowing users to recover passwords via email links and SMS codes

  • Encrypting data

Writing authentication routines

• An authentication routine is a method a programmer can use to ensure a user is entering the correct credentials to access a program or system

• The exam requirements are that students only need to be able to write plain text authentication routines and do not need to include encryption 

• The examples below will be written in Python

Example authentication code using an If statement

• This first program is a very simple version and would not be used in a real-world program

• This example demonstrates the fundamentals of how an authentication check would take place

username = input("Enter a username ")
password = input("Enter a password ")
if username == "SaveMyExams" and password == "coding":
    print("Welcome to the program"
else:
    print("Wrong details entered")

Example authentication code using a 2D array

• This second program is a better version which stores the usernames and passwords in a 2 dimensional array

• This example demonstrates how iteration and selection can be used together to store and retrieve information

#2d array containing the usernames and passwords
users = [

["Dave", "password"],

["Alice", "password2"],

["Bob", "password3"],

["Jane", "password4"]

]

#Asks for the user to input their username

username = input("Enter username: ")

#Loops through the array to find the username input by the user
for i in range (0,len(users)):

    if users[i][0] == username:
        #If the username is found, it will ask for their password

        password = input("Enter password: ")

        if users[i][1] == password:

            print("Welcome back " + username)

        else:

            print("Wrong password " + username)