Python: Cyber Security - Exercises, Practice, Solution

Python: Password cracking, hashing, policy enforcement and recovery [10 exercises with solution]

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1. Write a Python program that defines a function and takes a password string as input and returns its SHA-256 hashed representation as a hexadecimal string.
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2. Write a Python program that defines a function to generate random passwords of a specified length. The function takes an optional parameter length, which is set to 8 by default. If no length is specified by the user, the password will have 8 characters.
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3. Write a Python program to check if a password meets the following criteria:
At least 8 characters long and
Contains at least one uppercase letter, one lowercase letter, one digit, and one special character (!, @, #, $, %, or &)
If the password meets the criteria, print a message that says "Valid Password." If it doesn't meet the criteria, print a message that says "Password does not meet requirements."
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4. Write a Python function that takes a password as input and returns a list of common character substitutions that could be used to create a stronger password.
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5. Write a Python program that reads a file containing a list of passwords, one per line. It checks each password to see if it meets certain requirements (e.g. at least 8 characters, contains both uppercase and lowercase letters, and at least one number and one special character). Passwords that satisfy the requirements should be printed by the program.
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6. Write a Python program that reads a file containing a list of usernames and passwords, one pair per line (separatized by a comma). It checks each password to see if it has been leaked in a data breach. You can use the "Have I Been Pwned" API (https://haveibeenpwned.com/API/v3) to check if a password has been leaked.
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7. Write a Python program that creates a password strength meter. The program should prompt the user to enter a password and check its strength based on criteria such as length, complexity, and randomness. Afterwards, the program should provide suggestions for improving the password's strength.
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8. Write a Python program that generates a password using a random combination of words from a dictionary file.
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9. Write a Python program that simulates a dictionary attack on a password by trying out a list of commonly used passwords and their variations.
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10. Write a Python program that simulates a brute-force attack on a password by trying out all possible character combinations.
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