Python Cyber Security - Check password strength

Last update on April 03 2025 12:49:00 (UTC/GMT +8 hours)

3. Password Criteria Checker

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."

Sample Solution:

Python Code:

# Solution to Exercise 3
import re

def validate_password(password):
    # Check if the password has at least 8 characters
    if len(password) < 8:
        return False
    
    # Check if the password contains at least one uppercase letter
    if not re.search(r'[A-Z]', password):
        return False
    
    # Check if the password contains at least one lowercase letter
    if not re.search(r'[a-z]', password):
        return False
    
    # Check if the password contains at least one digit
    if not re.search(r'\d', password):
        return False
    
    # Check if the password contains at least one special character
    if not re.search(r'[!@#$%^&*(),.?":{}|<>]', password):
        return False
    
    # If all the conditions are met, the password is valid
    return True

password = input("Input your password: ")
is_valid = validate_password(password)

if is_valid:
    print("Valid Password.")
else:
    print("Password does not meet requirements.")

Sample Output:

Input your password:  Aji1#der
Valid Password.

Input your password:  A123d$%h
Valid Password. 

Input your password:  A12&ki1
Password does not meet requirements.

Input your password:  KI342$&H
Password does not meet requirements.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program that checks if a password meets complexity requirements (minimum 8 characters, at least one uppercase, one lowercase, one digit, and one special character) and prints either "Valid Password" or "Invalid Password" with specific missing criteria.
• Write a Python function that validates a password based on given rules and returns a tuple containing a boolean flag and a list of unmet requirements.
• Write a Python script that takes a list of passwords from the user, validates each one, and then prints a report showing which passwords are valid.
• Write a Python program to simulate a password policy check that allows re-tries until a valid password is entered, then confirms success.

Python Code Editor:

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