Public Key Infrastructure (PKI) in Cybersecurity - Mini Project: Build & Apply

Understanding Public Key Infrastructure (PKI)

📖 Scenario: You work in a company that wants to secure its online communications. Your task is to understand and build a simple model of Public Key Infrastructure (PKI) to see how digital certificates and keys work together to keep data safe.

🎯 Goal: Build a step-by-step model of PKI components using simple data structures to understand how keys and certificates are created, stored, and verified.

📋 What You'll Learn

Create a dictionary to represent users and their public keys

Add a variable to represent the Certificate Authority (CA) name

Create a function or logic to simulate issuing a digital certificate

Add a final step to simulate verifying a certificate using the CA

💡 Why This Matters

🌍 Real World

PKI is used to secure websites, emails, and software by ensuring that public keys are authentic and trusted.

💼 Career

Understanding PKI is essential for cybersecurity roles, network administrators, and software developers working on secure communications.

1

DATA SETUP: Create a dictionary of users and their public keys

Create a dictionary called users_public_keys with these exact entries: 'Alice': 'AlicePublicKey123', 'Bob': 'BobPublicKey456', 'Charlie': 'CharliePublicKey789'.

Cybersecurity

# Create the dictionary users_public_keys with the given entries
# Your code here

Need a hint?

Use curly braces to create a dictionary with keys as user names and values as their public keys.

2

CONFIGURATION: Add the Certificate Authority (CA) name

Create a variable called certificate_authority and set it to the string 'TrustedCA'.

Cybersecurity

users_public_keys = {
    'Alice': 'AlicePublicKey123',
    'Bob': 'BobPublicKey456',
    'Charlie': 'CharliePublicKey789'
}
# Create the variable certificate_authority with value 'TrustedCA'
# Your code here

Need a hint?

Just assign the string 'TrustedCA' to the variable certificate_authority.

3

CORE LOGIC: Simulate issuing digital certificates

Create a dictionary called digital_certificates where each key is a user name from users_public_keys and each value is a string combining the user's public key and the certificate_authority name separated by a dash. For example, for Alice it should be 'AlicePublicKey123-TrustedCA'.

Cybersecurity

users_public_keys = {
    'Alice': 'AlicePublicKey123',
    'Bob': 'BobPublicKey456',
    'Charlie': 'CharliePublicKey789'
}

certificate_authority = 'TrustedCA'
# Create digital_certificates by combining public keys and certificate_authority
# Your code here

Need a hint?

Use a dictionary comprehension to combine each public key with the certificate authority name.

4

COMPLETION: Simulate verifying a digital certificate

Create a function called verify_certificate that takes a certificate string and returns True if the certificate ends with the certificate_authority name, otherwise returns False.

Cybersecurity

users_public_keys = {
    'Alice': 'AlicePublicKey123',
    'Bob': 'BobPublicKey456',
    'Charlie': 'CharliePublicKey789'
}

certificate_authority = 'TrustedCA'

digital_certificates = {user: f"{key}-{certificate_authority}" for user, key in users_public_keys.items()}
# Define verify_certificate function to check certificate validity
# Your code here

Need a hint?

Use the string method endswith() to check if the certificate ends with the CA name.