Build a Secure Random Password Generator in Python

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In today’s digital world, password security is more important than ever. Weak or reused passwords can make your online accounts vulnerable to hacking.
In this tutorial, we’ll build a secure random password generator in Python using the built-in secrets and string modules.

This project is simple, beginner-friendly, and teaches you how to handle user input, loops, error handling, and random data generation safely.

The Complete Code

import secrets
import string

def generator_password():

    def generator_print(pass_length, special_char):
        password_to_create = ""
        while len(password_to_create) != pass_length:
            password_to_create += secrets.choice(special_char)
        return f"Generated password: {password_to_create}"
        
    while True:
        try: 
            password_length = int(
                input("Enter length of your password (at least 8 characters): ")
            )
            if password_length >= 8:
                break
            print("Password length must be at least 8 characters.")
            continue
        except ValueError:
            print("Please enter a valid number.")

    while True:
        include_special = input(
            "Include special characters? (yes/no): "
        ).lower()
        if include_special == "yes":
            chars = string.punctuation + string.ascii_letters + string.digits
            print(generator_print(password_length, chars))
        elif include_special == "no":
            chars = string.ascii_letters + string.digits
            print(generator_print(password_length, chars))
        else:
            print("Invalid answer. Please type 'yes' or 'no'.")
            continue
        break

generator_password()

Step-by-Step Explanation

Importing Modules

import secrets
import string

  • secrets: Used for generating cryptographically secure random numbers.

  • string: Provides useful character sets like letters, digits, and punctuation.

Defining the Main Function

def generator_password():

All the logic of the password generator is written inside this function.

Inner Function for Password Generation

def generator_print(pass_length, special_char):
password_to_create = ""
while len(password_to_create) != pass_length:
password_to_create += secrets.choice(special_char)
return f"Generated password: {password_to_create}"

  • This inner function creates the password.

  • It randomly picks characters (using secrets.choice) until the required length is reached.

  • Returns the generated password as a formatted string.

Taking Password Length Input

while True:
try:
password_length = int(input("Enter length of your password (at least 8 characters): "))
if password_length >= 8:
break
print("Password length must be at least 8 characters.")
continue
except ValueError:
print("Please enter a valid number.")

  • This loop ensures the user inputs a valid number.

  • The program repeats until the user provides a number ≥ 8.

Asking for Special Characters

while True:
include_special = input("Include special characters? (yes/no): ").lower()

  • Converts user input to lowercase for easy comparison.

  • If yes, it includes punctuation (like @, #, $, !) in the password.

  • If no, it only uses letters and digits.

Generating and Displaying the Password

Depending on the user’s choice:

if include_special == "yes":
chars = string.punctuation + string.ascii_letters + string.digits
print(generator_print(password_length, chars))
elif include_special == "no":
chars = string.ascii_letters + string.digits
print(generator_print(password_length, chars))

Finally, the password is generated and displayed on the screen.

Flowchart Explanation

Below is the logical flow of the program:

┌──────────────────────────────┐
│ Start Program │
└──────────────┬───────────────┘
│
▼
┌──────────────────────────────┐
│ Ask user for password length │
└──────────────┬───────────────┘
│
▼
┌────────────────────┐
│ Is input valid? │
└───────┬────────────┘
│Yes
▼
┌────────────────────┐
│ Length >= 8 ? │
└───────┬────────────┘
│Yes
▼
┌──────────────────────────────┐
│ Ask: Include special chars? │
│ (yes/no) │
└──────────────┬───────────────┘
│
▼
┌────────────────────┐
│ yes → letters + │
│ digits + symbols │
└────────┬───────────┘
│
│no
▼
┌────────────────────┐
│ letters + digits │
└────────┬───────────┘
│
▼
┌──────────────────────────────┐
│ Randomly generate characters │
│ until password is complete │
└──────────────┬───────────────┘
│
▼
┌──────────────────────────────┐
│ Print the generated password │
└──────────────┬───────────────┘
│
▼
┌──────────────────────────────┐
│ End │
└──────────────────────────────┘

Key Learnings

✅ Using secrets for secure randomness
✅ Validating user input with try–except
✅ Combining letters, digits, and symbols to make a strong password
✅ Applying loops and conditional logic in Python