Username/password authentication in IOT Protocols - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the username for authentication.

IOT Protocols

client.username_pw_set(username=[1])

Drag options to blanks, or click blank then click option'

A"admin"

B"mqtt"

C"password"

D"user123"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the password instead of the username.

Using a keyword like 'mqtt' instead of a username.

The username_pw_set method sets the username for the client. Here, "user123" is the correct username to use.

2fill in blank

medium

Complete the code to set the password for authentication.

IOT Protocols

client.username_pw_set(password=[1])

Drag options to blanks, or click blank then click option'

A"user123"

B"admin"

C"pass123"

D"mqtt"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the username instead of the password.

Using a keyword like 'mqtt' instead of a password.

The username_pw_set method sets the password for the client. Here, "pass123" is the correct password to use.

3fill in blank

hard

Fix the error in the code to correctly set username and password.

IOT Protocols

client.username_pw_set([1], [2])

Drag options to blanks, or click blank then click option'

A"user123", "pass123"

B"pass123", "user123"

C"user123"

D"pass123"

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping username and password arguments.

Passing only one argument instead of two.

The username_pw_set method takes the username as the first argument and the password as the second. Option A correctly orders them.

4fill in blank

hard

Fill both blanks to create a dictionary with username and password keys.

IOT Protocols

credentials = {"username": [1], "password": [2]

Drag options to blanks, or click blank then click option'

A"user123"

B"pass123"

C"admin"

D"guest"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up username and password values.

Using incorrect strings that don't represent credentials.

The dictionary keys "username" and "password" need values representing the user's login details. "user123" and "pass123" are the correct values.

5fill in blank

hard

Fill all three blanks to complete the function that sets username and password on a client.

IOT Protocols

def set_auth(client, [1], [2]):
    client.username_pw_set([3], [2])

Drag options to blanks, or click blank then click option'

Ausername

Bpassword

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent parameter names.

Swapping the order of username and password in the method call.

The function takes username and password as parameters. The method username_pw_set uses username first, then password.

Practice

1. What is the main purpose of username/password authentication in IoT protocols?

easy

A. To confirm the device identity before allowing connection

B. To encrypt the data sent between devices

C. To speed up the data transmission

D. To update the device firmware automatically

Solution

1. Step 1: Understand authentication role

   Username/password authentication is used to verify who is connecting to the system.

2. Step 2: Identify the purpose in IoT

   It confirms the device identity before connection to prevent unauthorized access.

3. Final Answer:

   To confirm the device identity before allowing connection -> Option A

4. Quick Check:

   Authentication = Confirm identity [OK]

Hint: Authentication means confirming identity before access [OK]

Common Mistakes:

• Confusing authentication with encryption
• Thinking it speeds up data transfer
• Assuming it updates firmware automatically

2. Which of the following is the correct syntax to include username and password in an MQTT connection string?

easy

A. mqtt://broker.example.com/username/password

B. mqtt://broker.example.com?user=username&pass=password

C. mqtt://broker.example.com#username=password

D. mqtt://username:[e-mail]

Solution

1. Step 1: Recall MQTT URI format

   The standard way to include username and password in MQTT URI is mqtt://username:password@host.

2. Step 2: Compare options

   mqtt://username:[e-mail] matches this format exactly, others use incorrect query or path syntax.

3. Final Answer:

   mqtt://username:[e-mail] -> Option D

4. Quick Check:

   Username:password@host = correct MQTT URI [OK]

Hint: Username and password go before @ in URI [OK]

Common Mistakes:

• Using query parameters instead of userinfo
• Placing credentials in URL path
• Using # fragment for credentials

3. Given this MQTT client connection code snippet, what will be the output if the username or password is incorrect?

client = mqtt.Client()
client.username_pw_set("user1", "wrongpass")
result = client.connect("broker.example.com")
print(result)

medium

A. 0

B. 1

C. 5

D. Connection refused error

Solution

1. Step 1: Understand MQTT connect return codes

   MQTT connect returns 0 on success, 5 means 'Not authorized' due to bad credentials.

2. Step 2: Analyze code behavior

   Since password is wrong, connect returns 5 indicating authentication failure.

3. Final Answer:

   5 -> Option C

4. Quick Check:

   Wrong password = return code 5 [OK]

Hint: MQTT connect returns 5 if authentication fails [OK]

Common Mistakes:

• Assuming 0 means failure
• Expecting an exception instead of return code
• Confusing return codes with error messages

4. You wrote this code to connect with username/password but always get connection refused. What is the likely error?

client = mqtt.Client()
client.username_pw_set(user="admin", password="1234")
client.connect("broker.example.com")

medium

A. The username_pw_set method parameters are incorrect

B. The broker address is invalid

C. The client object is not created properly

D. The connect method is missing a port number

Solution

1. Step 1: Check username_pw_set method signature

   The correct parameters are username and password, not user and password.

2. Step 2: Identify impact of wrong parameter names

   Passing wrong parameter names means username and password are not set, causing authentication failure.

3. Final Answer:

   The username_pw_set method parameters are incorrect -> Option A

4. Quick Check:

   Correct param names = username, password [OK]

Hint: Use 'username' not 'user' in username_pw_set() [OK]

Common Mistakes:

• Using 'user' instead of 'username'
• Ignoring parameter names and order
• Assuming default port fixes auth errors

5. You want to secure your IoT device connection using username/password authentication over MQTT. Which combination of steps ensures best security practice?

hard

A. Use simple passwords for easy access and disable encryption for speed

B. Use strong unique passwords, enable TLS encryption, and never hardcode credentials

C. Share username/password openly in device logs for troubleshooting

D. Use default credentials and rely on network firewall only

Solution

1. Step 1: Identify secure password practices

   Strong unique passwords prevent easy guessing or brute force attacks.

2. Step 2: Use encryption and protect credentials

   Enabling TLS encrypts data and prevents credential theft; never hardcoding avoids leaks.

3. Final Answer:

   Use strong unique passwords, enable TLS encryption, and never hardcode credentials -> Option B

4. Quick Check:

   Strong passwords + TLS + no hardcoding = secure [OK]

Hint: Strong passwords + TLS + no hardcoding = secure IoT auth [OK]

Common Mistakes:

• Using weak or default passwords
• Disabling encryption for convenience
• Exposing credentials in logs