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Scofield Idehen
Scofield Idehen

Posted on • Originally published at blog.learnhub.africa

Build a Secure Python Password Generator Using Secret Lib

After building the Password Generator, I got some amazing reviews, and two stood out for me: Guillaume Ste-Marie advocated using seed to increase the randomness, and Christian Ledermann also advocated that secrets should replace random as random is not really random.

The secrets module generates cryptographically strong random numbers suitable for managing data such as passwords, account authentication, security tokens, and related secrets.

The Complete Secure Password Generator Code

Let's start by looking at the entire code for our secure password generator. Don't worry if it looks intimidating; we'll break it down line by line in the next section.

    import secrets
    import string

    def generate_password(length=12):
        characters = string.ascii_letters + string.digits + string.punctuation
        password = ''.join(secrets.choice(characters) for _ in range(length))
        return password

    def main():
        print("Welcome to the Secure Password Generator!")

        try:
            length = int(input("Enter the desired password length: "))
            if length <= 0:
                raise ValueError("Password length must be positive")
        except ValueError as e:
            print(f"Invalid input: {e}")
            print("Using default length of 12 characters.")
            length = 12

        password = generate_password(length)
        print(f"\nYour generated password is: {password}")

    if __name__ == "__main__":
        main()
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Now, let's break this down and examine each part in detail.

Importing Necessary Modules

    import secrets
    import string
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These two lines import the modules we need for our secure password generator:

  • The secrets module provides functions for generating cryptographically strong random numbers suitable for managing secrets such as passwords. It's more secure than the random module for cryptographic purposes.

  • The string module offers constants containing various types of characters (letters, digits, punctuation). This saves us from manually typing out all possible characters we might want in a password.

    The generate_password Function

    def generate_password(length=12):
        characters = string.ascii_letters + string.digits + string.punctuation
        password = ''.join(secrets.choice(characters) for _ in range(length))
        return password
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This function generates our secure password:

  • We create a string characters containing all possible characters for our password.

  • We use secrets.choice() to randomly select characters from this string. This is more secure than using random.choice() because it uses the operating system's cryptographically secure random number generator.

  • We join these characters into a single string to form our password.

    The main Function

    def main():
        print("Welcome to the Secure Password Generator!")

        try:
            length = int(input("Enter the desired password length: "))
            if length <= 0:
                raise ValueError("Password length must be positive")
        except ValueError as e:
            print(f"Invalid input: {e}")
            print("Using default length of 12 characters.")
            length = 12

        password = generate_password(length)
        print(f"\nYour generated password is: {password}")
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This function handles user interaction:

  • It prompts the user for a password length.
  • It handles potential errors (like non-numeric input or negative numbers).
  • It calls generate_password() with the specified length and prints the result. ## Running the Script
    if __name__ == "__main__":
        main()
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This block ensures that the main() function is only called if the script is run directly, not if it's imported as a module.

Enhancing the Password Generator

Here are some ideas to further improve your password generator:

  1. Custom Character Sets: Allow users to specify which types of characters they want in their password.
  2. Password Strength Checker: Implement a function to evaluate the strength of the generated password.
  3. Multiple Passwords: Give users the option to generate multiple passwords at once.
  4. GUI Interface: Create a graphical user interface using a library like Tkinter.
  5. Password Storage: Implement a secure way to store generated passwords, possibly with encryption. ## Conclusion

By using the secrets module instead of random, we've created a more secure password generator.

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