Before a system can control what a user is allowed to do, it must first confirm who the user is. This process is known as authentication. In IB Computer Science, students are expected to understand different authentication methods, how they work, and their strengths and weaknesses.
IB examiners reward answers that compare methods rather than simply listing them.
What Is Authentication?
Authentication is the process of:
- Verifying a user’s identity
- Ensuring they are who they claim to be
Authentication occurs before authorisation.
- Authentication: Who are you?
- Authorisation: What are you allowed to do?
Understanding this sequence is essential for IB exams.
Password-Based Authentication
Passwords are the most common authentication method.
They rely on:
- Something the user knows
How Passwords Work
- The user enters a secret string
- The system checks it against stored credentials
Advantages
- Simple to implement
- Low cost
- Familiar to users
Disadvantages
- Weak passwords are easy to guess
- Password reuse increases risk
- Can be stolen through phishing or malware
IB students should explain that passwords are convenient but vulnerable.
Biometric Authentication
Biometric authentication relies on:
- Something the user is
Common biometric methods include:
- Fingerprints
- Facial recognition
- Iris or retina scans
How Biometrics Work
- Physical traits are scanned
- Compared against stored biometric data
Advantages
- Difficult to copy or share
- Convenient for users
- No need to remember secrets
Disadvantages
- Privacy concerns
- False positives or false negatives
- Cannot be changed if compromised
IB examiners often expect students to mention privacy risks.
Token-Based Authentication
Token-based authentication relies on:
- Something the user has
Examples include:
- Key cards
- One-time password generators
- Mobile authentication apps
How Tokens Work
- The user possesses a physical or digital token
- The system verifies the token’s value
Advantages
- Harder to steal remotely
- Reduces reliance on memory
Disadvantages
- Tokens can be lost or stolen
- Additional cost
- Requires extra devices
Tokens are commonly used in secure systems.
Multi-Factor Authentication (MFA)
Many systems combine methods using multi-factor authentication.
MFA requires:
- Two or more authentication factors
For example:
- Password + fingerprint
- Password + one-time code
MFA significantly improves security by reducing reliance on a single method.
Comparing Authentication Methods
Strong IB answers compare methods clearly:
- Passwords: convenient but vulnerable
- Biometrics: secure but raise privacy issues
- Tokens: secure but require physical possession
No single method is perfect.
Choosing the Right Method
The best authentication method depends on:
- Security requirements
- User convenience
- Cost
- Privacy concerns
High-security systems often use MFA.
Common Student Mistakes
Students often:
- Confuse authentication with authorisation
- Ignore disadvantages
- Assume biometrics are flawless
- Forget MFA
Balanced evaluation earns higher marks.
How This Appears in IB Exams
IB questions may ask students to:
- Explain an authentication method
- Compare different methods
- Justify a choice for a scenario
- Discuss strengths and weaknesses
Explanation matters more than memorisation.
Final Thoughts
Authentication confirms a user’s identity using passwords, biometrics, tokens, or a combination of methods. Each approach has strengths and weaknesses, and secure systems often use multiple factors.
Understanding authentication methods allows IB Computer Science students to explain access control systems clearly and confidently — exactly what examiners expect.
