Username/password authentication in IOT Protocols - Mini Project: Build & Apply

Username/password authentication

📖 Scenario: You are setting up a simple username and password authentication system for an IoT device. This device needs to check if the user credentials are correct before allowing access.

🎯 Goal: Build a small program that stores a username and password, sets a login attempt, checks if the credentials match, and prints whether access is granted or denied.

📋 What You'll Learn

Create variables for username and password with exact values

Create variables for login attempt username and password

Write a condition to check if login attempt matches stored credentials

Print 'Access granted' if credentials match, otherwise print 'Access denied'

💡 Why This Matters

🌍 Real World

IoT devices often require simple username and password checks to allow authorized users to control or configure them.

💼 Career

Understanding basic authentication logic is important for DevOps roles managing device security and access control.

1

Create stored username and password

Create a variable called stored_username and set it to "admin". Create a variable called stored_password and set it to "iot1234".

IOT Protocols

# Create stored username and password variables
# Your code here

Hint

Use simple string assignment like variable = "value".

2

Create login attempt variables

Create a variable called login_username and set it to "admin". Create a variable called login_password and set it to "iot1234".

IOT Protocols

stored_username = "admin"
stored_password = "iot1234"
# Create login attempt username and password variables
# Your code here

Hint

Use the same string assignment method as before.

3

Check if login credentials match

Write an if statement that checks if login_username equals stored_username and login_password equals stored_password.

IOT Protocols

stored_username = "admin"
stored_password = "iot1234"
login_username = "admin"
login_password = "iot1234"
# Write if condition to check credentials
# Your code here

Hint

Use and to combine two conditions in the if statement.

4

Print access result

Write a print statement that prints "Access granted" if access_granted is True, otherwise print "Access denied".

IOT Protocols

stored_username = "admin"
stored_password = "iot1234"
login_username = "admin"
login_password = "iot1234"
if login_username == stored_username and login_password == stored_password:
    access_granted = True
else:
    access_granted = False
# Print access result
# Your code here

Hint

Use an if statement to print the correct message based on access_granted.

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