token_generator.py

#!/usr/bin/python
# Basic HOTP / TOTP Generator using integers or strings as seeds
#
# Requirements:
# * Python 3
# * pyotp library (pip install pyotp)
#
# Usage:
# python token.py
#
# Try entering the seed in 'string' mode if 'integer' fails.
#
import pyotp
import time
import base64

# Function to generate HOTP or TOTP
def generate_otp(secret_seed, choice, counter_or_time=None):
    # Convert the secret seed (integer) to a byte string and then encode it in base32
    if isinstance(secret_seed, int):
        # Endianess might be wrong. If this script fails to generate a valid code for your use case, change the byteorder from 'big' to 'little'.
        secret_bytes = secret_seed.to_bytes((secret_seed.bit_length() + 7) // 8, byteorder='big')
    else:
        # If it's in string mode, simply encode it
        secret_bytes = secret_seed.encode('utf-8')

    secret_base32 = base64.b32encode(secret_bytes).decode('utf-8').strip('=')
    print(f"Base32: {secret_base32}")

    if choice == 'HOTP' and counter_or_time is not None:
        # HOTP: Requires a counter
        totp = pyotp.HOTP(secret_base32)
        otp = totp.at(counter_or_time)  # For HOTP use counter
        print(f"HOTP: {otp}")
    elif choice == 'TOTP':
        # TOTP: Uses the current time (based on 30-second intervals)
        totp = pyotp.TOTP(secret_base32)
        otp = totp.now()  # For TOTP use the current time
        print(f"TOTP: {otp}")
    else:
        print("Invalid input, please enter 'HOTP' or 'TOTP'.")

# Function to input and validate the seeds
def input_seeds():
    while True:
        seed_type = input("Would you like to use an integer or a string as the secret key? (Enter 'integer' or 'string'): ").strip().lower()

        if seed_type == 'integer':
            try:
                secret_seed = int(input("Enter the secret key (integer): "))
                return secret_seed  # Return as integer
            except ValueError:
                print("Invalid input. Please enter a valid integer.")

        elif seed_type == 'string':
            secret_seed = str(input("Enter the secret key (string): "))
            return secret_seed  # Return as string

        else:
            print("Invalid choice. Please enter 'integer' or 'string'.")

def main():
    print("OATH HOTP/TOTP OTP Generator")

    # Ask user whether to generate HOTP or TOTP first
    choice = input("Would you like to generate HOTP or TOTP? (Enter 'HOTP' or 'TOTP'): ").strip().upper()

    if choice == 'HOTP':
        secret_seed = input_seeds()
        counter = int(input("Enter the counter (integer): "))  # HOTP requires a counter
        generate_otp(secret_seed, choice, counter)
    elif choice == 'TOTP':
        secret_seed = input_seeds()
        generate_otp(secret_seed, choice)  # TOTP doesn't need a counter
    else:
        print("Invalid choice. Please enter 'HOTP' or 'TOTP'.")

if __name__ == "__main__":
    main()