Python Cyber Security - Function to suggest character substitutions for stronger passwords

Last update on April 24 2025 12:32:38 (UTC/GMT +8 hours)

4. Common Substitution Generator

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.

For example, if the password is "myspass", the function should return

['my$pass', 'my5pass', 'mySpass', 'mysp@ss', 'mysp4ss', 'myspAss', 'myspa$s', 'myspa5s', 'myspaSs', 'myspas$', 'myspas5', 'myspasS', 'myspass!', 'myspass123', 'myspass@', 'myspass#', 'myspass$', 'myspass%', 'myspass&', 'myspass*', 'myspass-', 'myspass_', 'myspass=', 'myspass+']

Sample Solution:

Python Code:

def get_password_variants(password):
    pass_variants = []
    substitutions = {
        'a': ['@', '4', 'A'],
        'e': ['3', 'E'],
        'i': ['1', '!', 'I'],
        'o': ['0', 'O'],
        's': ['$', '5', 'S'],
        't': ['7', 'T'],
        'z': ['2', 'Z']
    }
    
    for i in range(len(password)):
        if password[i] in substitutions:
            for sub in substitutions[password[i]]:
                pass_variant = password[:i] + sub + password[i+1:]
                pass_variants.append(pass_variant)
    
    pass_variants.append(password + '!')
    pass_variants.append(password + '123')
    pass_variants.append(password + '@')
    pass_variants.append(password + '#')
    pass_variants.append(password + '$')
    pass_variants.append(password + '%')
    pass_variants.append(password + '&')
    pass_variants.append(password + '*')
    pass_variants.append(password + '-')
    pass_variants.append(password + '_')
    pass_variants.append(password + '=')
    pass_variants.append(password + '+')    
    return pass_variants
password = input("Input your password: ")
result_variants = get_password_variants(password)
print(result_variants)

Sample Output:

Input your password:  pqre3sd
['pqr33sd', 'pqrE3sd', 'pqre3$d', 'pqre35d', 'pqre3Sd', 'pqre3sd!', 'pqre3sd123', 'pqre3sd@', 'pqre3sd#', 'pqre3sd$', 'pqre3sd%', 'pqre3sd&', 'pqre3sd*', 'pqre3sd-', 'pqre3sd_', 'pqre3sd=', 'pqre3sd+']

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python function that takes a password and returns a dictionary mapping each character to a list of common substitutions (e.g., 'a' to ['@', '4']).
Write a Python program to generate a list of possible stronger passwords by replacing characters in the input password with their common substitutions.
Write a Python script that, given a password, prints out all variant forms using at least one substitution for each character.
Write a Python function that takes a password and returns all combinations of substitutions for its characters, filtering out duplicates.

Go to:

Previous: Check password strength.
Next: Check and print valid passwords from a file.

Python Code Editor:

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