🔐 Build a Password Generator and Strength Checker

Use the secrets module — not random — for cryptographically secure passwords. The secrets module is specifically designed for generating tokens and passwords.

import secrets
import string

def generate_password(length=16, use_upper=True, use_digits=True, use_symbols=True):
    chars = string.ascii_lowercase
    if use_upper:   chars += string.ascii_uppercase
    if use_digits:  chars += string.digits
    if use_symbols: chars += string.punctuation

    # secrets.choice is cryptographically secure (unlike random.choice)
    password = ''.join(secrets.choice(chars) for _ in range(length))
    return password

# Generate a few
for _ in range(5):
    print(generate_password(16))

mK9#vLpX2@nRqT8w
Yz7$bNsQ4&hJcW3e
aP5!dFxM1*kUiG6r
Bj8^oEtH3%lVnC0y
wR2@sIpA9#mZqD7f

Score the password on five criteria: length, uppercase, lowercase, digits, and symbols.

import re

def check_strength(password):
    score = 0
    feedback = []

    checks = [
        (len(password) >= 8,  '+1  Length >= 8 characters'),
        (len(password) >= 14, '+1  Length >= 14 characters (bonus)'),
        (bool(re.search(r'[A-Z]', password)), '+1  Contains uppercase letters'),
        (bool(re.search(r'[a-z]', password)), '+1  Contains lowercase letters'),
        (bool(re.search(r'\d',    password)), '+1  Contains numbers'),
        (bool(re.search(r'[^A-Za-z0-9]', password)), '+1  Contains symbols'),
    ]

    for passed, message in checks:
        if passed:
            score += 1
            feedback.append(f'  ✅ {message}')
        else:
            feedback.append(f'  ❌ {message}')

    labels = {6: 'VERY STRONG', 5: 'STRONG', 4: 'GOOD', 3: 'FAIR', 2: 'WEAK', 1: 'VERY WEAK', 0: 'TERRIBLE'}
    bars   = {6: '██████', 5: '█████░', 4: '████░░', 3: '███░░░', 2: '██░░░░', 1: '█░░░░░', 0: '░░░░░░'}

    return score, labels.get(score, 'WEAK'), bars.get(score, '░░░░░░'), feedback

score, label, bar, tips = check_strength("hello123")
print(f'Strength: {bar} {label} ({score}/6)\n')
for tip in tips:
    print(tip)

Strength: ███░░░ FAIR (3/6)

  ✅ +1  Length >= 8 characters
  ❌ +1  Length >= 14 characters (bonus)
  ❌ +1  Contains uppercase letters
  ✅ +1  Contains lowercase letters
  ✅ +1  Contains numbers
  ❌ +1  Contains symbols

def main():
    print("=" * 45)
    print("  🔐  Password Tool")
    print("=" * 45)

    while True:
        print("\n1. Generate a password")
        print("2. Check password strength")
        print("3. Exit")
        choice = input("\nChoice: ").strip()

        if choice == '1':
            try:
                length = int(input("Length (default 16): ").strip() or 16)
            except ValueError:
                length = 16
            use_symbols = input("Include symbols? (y/n, default y): ").lower() != 'n'

            pwd = generate_password(length, use_symbols=use_symbols)
            print(f"\nGenerated: {pwd}")

            score, label, bar, tips = check_strength(pwd)
            print(f"Strength:  {bar} {label} ({score}/6)")

        elif choice == '2':
            pwd = input("Enter password to check: ")
            score, label, bar, tips = check_strength(pwd)
            print(f"\nStrength: {bar} {label} ({score}/6)\n")
            for tip in tips:
                print(tip)

        elif choice == '3':
            print("Goodbye!")
            break

if __name__ == '__main__':
    main()

=============================================
  🔐  Password Tool
=============================================

1. Generate a password
2. Check password strength
3. Exit

Choice: 1
Length (default 16): 20
Include symbols? (y/n, default y): y

Generated: mK9#vLpX2@nRqT8w!eBz
Strength:  ██████ VERY STRONG (6/6)