60 lines
1.6 KiB
Python
60 lines
1.6 KiB
Python
"""Password hashing and opaque token helpers."""
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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 secrets
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def hash_password(password: str) -> str:
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salt = secrets.token_bytes(16)
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derived = hashlib.scrypt(password.encode("utf-8"), salt=salt, n=16384, r=8, p=1)
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return "scrypt$16384$8$1${}${}".format(
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base64.b64encode(salt).decode("ascii"),
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base64.b64encode(derived).decode("ascii"),
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)
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def verify_password(password: str, encoded: str | None) -> bool:
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if not encoded:
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return False
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try:
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algorithm, n_value, r_value, p_value, salt_encoded, digest_encoded = encoded.split("$", maxsplit=5)
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except ValueError:
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return False
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if algorithm != "scrypt":
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return False
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salt = base64.b64decode(salt_encoded.encode("ascii"))
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expected = base64.b64decode(digest_encoded.encode("ascii"))
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actual = hashlib.scrypt(
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password.encode("utf-8"),
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salt=salt,
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n=int(n_value),
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r=int(r_value),
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p=int(p_value),
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)
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return hmac.compare_digest(actual, expected)
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def generate_token() -> str:
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return secrets.token_urlsafe(32)
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def hash_token(token: str) -> str:
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return hashlib.sha256(token.encode("utf-8")).hexdigest()
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def token_prefix(token: str) -> str:
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return token[:8]
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def mask_secret(value: str, *, prefix: int = 6, suffix: int = 4, mask_char: str = "*") -> str:
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text = (value or "").strip()
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if not text:
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return ""
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if len(text) <= prefix + suffix:
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return mask_char * len(text)
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hidden = len(text) - prefix - suffix
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return f"{text[:prefix]}{mask_char * hidden}{text[-suffix:]}" |