Generate UCAM COVID testing barcodes

#!/usr/bin/env python3
import base64
import hashlib
import secrets


def gen_code():
    """
    Generate a random barcode identifier corresponding to the current strawman
    proposal.

    https://docs.google.com/document/d/1td8uYbrubzXGzsYI95tqQU_O6rmwWsaBwAHH-JIDPOE/edit

    """
    sample_id = secrets.token_bytes(8)
    payload = base64.b32encode(sample_id).rstrip(b'=')

    check_digest = hashlib.sha256()
    check_digest.update(payload)
    check_payload = base64.b32encode(check_digest.digest()[:3]).rstrip(b'=')

    return f'UCAM-{payload.decode("ascii")}-{check_payload.decode("ascii")}'


def main():
    for _ in range(10):
        print(gen_code())


if __name__ == '__main__':
    main()