python 3.10 flask app pin generator

flask_pin_calc.py

import hashlib
from itertools import chain

probably_public_bits = [
    "user", # exec username
    "flask.app", # default
    "wsgi_app", # <= uvicorn, default "Flask"
    "/venv/lib/python3.10/site-packages/flask/app.py" # app.py or app.pyc
]

private_bits = [
    '4883362083', # /proc/net/arp, /sys/class/net/eth0/address, => 0x123123123 => 4883362083
    'XXXXXXXXXXXXXXhoge.hoge' # /etc/machine-id + (. /proc/self/cgroup or blank)
]

h = hashlib.sha1() # old h = hashlib.md5() 
for bit in chain(probably_public_bits, private_bits):
    if not bit:
        continue
    if isinstance(bit, str):
        bit = bit.encode("utf-8")
    h.update(bit)

h.update(b"cookiesalt") # or h.update(b'shittysalt')
cookie_name = f"__wzd{h.hexdigest()[:20]}"

h.update(b"pinsalt")
num = f"{int(h.hexdigest(), 16):09d}"[:9]

for group_size in 5, 4, 3:
    if len(num) % group_size == 0:
        rv = "-".join(
            num[x : x + group_size].rjust(group_size, "0")
            for x in range(0, len(num), group_size)
        )
        break
else:
    rv = num

print(rv)