Secure Authentication Techniques for Mobile Apps Quiz

Explore essential secure authentication methods used in mobile apps and evaluate your understanding of best practices, vulnerabilities, and user security concepts. This quiz covers key aspects such as biometrics, two-factor authentication, token handling, and password management in the context of mobile application security.

1. Password Storage Practices

   Which is the safest way to store user passwords in a mobile app’s backend server?

   1. Encrypting passwords using reversible encryption
   2. Hashing passwords with a strong, salted hash function
   3. Saving passwords in a shared document
   4. Storing passwords as plain text

   Explanation: Hashing passwords with salt ensures that even if attackers obtain the password database, they cannot easily recover the original passwords. Storing passwords in plain text or using reversible encryption makes them accessible if the system is compromised. Saving passwords in a shared document is insecure and unprofessional. Salting and hashing greatly enhance password security.

2. Multi-factor Authentication Advantage

   Why does enabling two-factor authentication (2FA) improve account security in mobile apps?

   1. It requires users to remember only one password
   2. It allows easier password resets
   3. It disables account lockout features
   4. It adds a second layer of verification beyond a password

   Explanation: Two-factor authentication improves security by requiring both something the user knows (like a password) and something they have or are (like a device or biometric trait). Remembering one password or easier password resets are not related to the main benefit. Disabling account lockouts would actually decrease security.

3. Biometric Authentication Security

   Which statement best describes the secure use of biometric authentication (such as fingerprint or face recognition) in mobile apps?

   1. Biometrics replace all need for strong passwords
   2. Using biometrics always removes the risk of unauthorized access
   3. Biometric data should be stored securely on the device, not transmitted to servers
   4. Storing biometric data in plain text on cloud servers is acceptable

   Explanation: Storing biometric data locally and securely reduces exposure to breaches and keeps personal data private. Biometrics are not a replacement for all password requirements and still need secure storage. Sending plain text data over the internet is a severe security risk. While biometrics improve convenience, they don’t eliminate all unauthorized access risks.

4. Session Token Management

   What is a critical best practice for handling session tokens in mobile applications?

   1. Send session tokens over unencrypted HTTP
   2. Store session tokens in secure storage, like the keychain or secure enclave
   3. Write session tokens directly in app logs
   4. Never expire session tokens

   Explanation: Storing tokens in secure, device-specific storage prevents unauthorized access. Sending tokens over unencrypted connections, failing to expire them, or writing them in logs exposes them to attackers. Proper storage helps protect user sessions from theft or misuse.

5. OAuth 2.0 Usage

   When using OAuth 2.0 in a mobile app, which is the most secure way to handle the access token?

   1. Use secure storage and set appropriate token expiration
   2. Share the token between different users on the same device
   3. Transmit tokens on paper for backup
   4. Store the access token in an unprotected text file on the device

   Explanation: Securing tokens with device-level protection and ensuring tokens expire limits the risk if a device is lost or stolen. Storing tokens in unprotected files or sharing them between users increases the chance of compromise. Physical transmission of tokens is ineffective and not suitable for digital security.

6. One-Time Passwords (OTP) Benefit

   How do one-time passwords (OTPs) sent to a user’s mobile device enhance security when logging into an app?

   1. OTPs are valid for long periods
   2. OTPs are usable only once, reducing the risk from password reuse
   3. They allow permanent access without a password
   4. They replace the need for all authentication methods

   Explanation: OTPs improve security by being valid for a single session, so stolen OTPs cannot be reused. They do not provide permanent access or eliminate the need for all other authentication. Long validity for OTPs is insecure and defeats their purpose.

7. Insecure Authentication Example

   Which is an example of an insecure authentication practice in mobile app development?

   1. Using device-based biometrics
   2. Authenticating over HTTPS
   3. Transmitting passwords in plain text over the network
   4. Storing passwords with a salt

   Explanation: Sending passwords without encryption exposes them to anyone intercepting network traffic. Authentication over HTTPS, password salting, and device biometrics are all security enhancements. Plain text transmission is widely regarded as unsafe.

8. Password Complexity Importance

   Why is enforcing password complexity important in mobile app authentication?

   1. It causes users to write passwords on paper
   2. It makes brute-force attacks more difficult
   3. It prevents all types of hacking
   4. It makes passwords easier to guess

   Explanation: Complex passwords are harder for attackers to guess using automated methods, improving security. Complexity doesn't prevent all hacking and doesn't necessarily lead users to unsafe behaviors like writing passwords down. Less complex passwords are far easier to breach.

9. User Session Timeout

   What is the main reason to implement automatic session timeout after inactivity in a mobile app?

   1. To save battery power
   2. To increase app launch speed
   3. To force frequent user logins for convenience
   4. To reduce the risk if a device is lost or left unattended

   Explanation: Session timeouts help prevent unauthorized access when a device is left unattended. Frequent logins are not convenient for users but serve a security purpose. Battery savings or launch speed are unrelated to session management.

10. Social Login Security

    Which practice helps ensure secure social login integration in a mobile app?

    1. Trusting any third-party login attempt without verification
    2. Validating the authentication response from the social provider
    3. Ignoring authentication token expiration
    4. Allowing login without redirecting to the social provider

    Explanation: Validating responses confirms the user’s identity and prevents unauthorized access. Trusting logins without checks or ignoring token expiration opens security holes. Direct logins without redirection fail to leverage the security provided by established providers.