otp.py

import time
import random
import hashlib
import os

def encode_with_otp(pw: str) -> str:
    CHARS = os.getenv("CHARS")
    seed = seed_from_timestamp(str(timestamp_in_minutes()))
    random.seed(seed)
    otp = ""
    length = len(CHARS)

    for s in range(256):
        otp += CHARS[int(random.random() * length)]

    return shuffle(otp, pw)


def seed_from_timestamp(t: str) -> int:
    h = hashlib.sha256((t + os.getenv("TIMESTAMP_SALT")).encode())
    return int.from_bytes(h.digest(), 'big')


def shuffle(otp: str, pw: str) -> str:
    o = list(otp+pw)
    random.shuffle(o)
    return "".join(o)


def timestamp_in_minutes() -> int:
    return int(time.time() / 60)