Digital signatures in Cybersecurity - Mini Project: Build & Apply

Understanding Digital Signatures

📖 Scenario: You work in a company that needs to ensure the authenticity and integrity of important documents shared via email. Your task is to understand how digital signatures work to protect these documents from tampering and impersonation.

🎯 Goal: Build a simple conceptual model of a digital signature process using clear steps and explanations. This will help you grasp how digital signatures verify the sender's identity and ensure the document has not been changed.

📋 What You'll Learn

Create a dictionary called document with keys content and sender and their exact values

Add a variable called private_key with the exact string value representing the sender's private key

Create a function called sign_document that takes document and private_key and returns a signature string

Add a final step to simulate attaching the signature to the document in a dictionary called signed_document

💡 Why This Matters

🌍 Real World

Digital signatures are used to ensure that electronic documents are authentic and have not been altered, which is essential in legal, financial, and communication fields.

💼 Career

Understanding digital signatures is important for cybersecurity professionals, software developers, and anyone involved in secure digital communications.

1

Create the document data

Create a dictionary called document with the keys content set to 'Confidential report data' and sender set to 'Alice'.

Cybersecurity

# Create the document dictionary with content and sender
# Your code here

Need a hint?

Use curly braces to create a dictionary with the exact keys and values.

2

Add the sender's private key

Add a variable called private_key and set it to the string 'AlicePrivateKey123'.

Cybersecurity

document = {'content': 'Confidential report data', 'sender': 'Alice'}
# Add the private_key variable with the exact string value
# Your code here

Need a hint?

Assign the exact string to the variable private_key.

3

Create the signing function

Define a function called sign_document that takes two parameters: document and private_key. Inside the function, create a signature string by combining the document's content and the private key separated by a dash, and return this signature string.

Cybersecurity

document = {'content': 'Confidential report data', 'sender': 'Alice'}
private_key = 'AlicePrivateKey123'
# Define the sign_document function below
# Your code here

Need a hint?

Use string concatenation with a dash between content and private_key, then return the result.

4

Attach the signature to the document

Create a dictionary called signed_document that contains all keys and values from document and add a new key signature with the value returned by calling sign_document(document, private_key).

Cybersecurity

document = {'content': 'Confidential report data', 'sender': 'Alice'}
private_key = 'AlicePrivateKey123'

def sign_document(document, private_key):
    signature = document['content'] + '-' + private_key
    return signature

# Create signed_document dictionary with document data and signature
# Your code here

Need a hint?

Use document.copy() to copy the dictionary and add the signature key with the function call result.