62 lines
1.5 KiB
Python
62 lines
1.5 KiB
Python
from __future__ import annotations
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import base64
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import hashlib
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import hmac
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import os
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_ALGORITHM = "pbkdf2_sha256"
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_DEFAULT_ITERATIONS = 260_000
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_SALT_BYTES = 16
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def hash_participant_password(
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password: str,
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*,
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iterations: int = _DEFAULT_ITERATIONS,
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) -> str:
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"""Hash a public-participant access password for durable storage."""
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salt = os.urandom(_SALT_BYTES)
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digest = hashlib.pbkdf2_hmac(
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"sha256",
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password.encode("utf-8"),
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salt,
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iterations,
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)
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return "$".join(
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(
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_ALGORITHM,
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str(iterations),
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base64.b64encode(salt).decode("ascii"),
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base64.b64encode(digest).decode("ascii"),
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)
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)
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def verify_participant_password(password: str, encoded: str | None) -> bool:
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"""Verify a participant password without exposing the stored hash."""
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if not encoded:
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return False
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try:
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algorithm, iterations_text, salt_b64, digest_b64 = encoded.split("$", 3)
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if algorithm != _ALGORITHM:
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return False
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iterations = int(iterations_text)
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salt = base64.b64decode(salt_b64.encode("ascii"), validate=True)
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expected = base64.b64decode(digest_b64.encode("ascii"), validate=True)
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except (TypeError, ValueError):
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return False
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actual = hashlib.pbkdf2_hmac(
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"sha256",
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password.encode("utf-8"),
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salt,
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iterations,
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)
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return hmac.compare_digest(actual, expected)
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__all__ = ["hash_participant_password", "verify_participant_password"]
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