A free, time-based OTP generator(client). Based on RFC-6238 spec.

1. Requires python3.

   brew install python3

2. Setup virtual environment

   python3 -m venv env

3. Activate virtual environment

   source env/bin/activate

4. Run the app locally

   python app.py

5. Deploy it in a cloud function or run the flask server locally :)

6. If you want to execute this as a regular python script to try it out

   python3 local.py <<< base32encodedString or python3 local.py <<< hexEncodedString

If you want to refactor the code as a HOTP generator, replace the get_number_of_time_steps with your counter and that should do the trick.

Sample input: http://127.0.0.1:5000/generate?code=1d319930bdb2ea7d580080f637cd9e53d6ef1767&digits=6

code is the secret key for the SHA-1 hash(hex encoded) OR use a base32 secret key. digits is number of digits you want the algorithm to return (max 8). alg is the type of SHA algorithm to be used based on the code provided. SHA-1, SHA-256, SHA-512 supported.

If you're a fan of the curl command:

curl -X GET "http://127.0.0.1:5000/generate?code=base32encodedString&digits=6&alg=sha1"

To verify that the generator is working as expected

1. Scan the QR code from website https://www.xanxys.net/totp/ on an authenticator app
2. Use the link above in sample and hit the server (running on your machine). The site uses SHA-1 codes.
3. Response from the Flask app and your authenticator app should match.

Here is a sample output: