JFIF$        dd7 

Viewing File: /usr/lib64/python3.9/site-packages/cryptography/hazmat/primitives/kdf/concatkdf.py

# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.


import struct
import typing

from cryptography import utils
from cryptography.exceptions import (
    AlreadyFinalized,
    InvalidKey,
)
from cryptography.hazmat.primitives import constant_time, hashes, hmac
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction


def _int_to_u32be(n: int) -> bytes:
    return struct.pack(">I", n)


def _common_args_checks(
    algorithm: hashes.HashAlgorithm,
    length: int,
    otherinfo: typing.Optional[bytes],
) -> None:
    max_length = algorithm.digest_size * (2 ** 32 - 1)
    if length > max_length:
        raise ValueError(
            "Cannot derive keys larger than {} bits.".format(max_length)
        )
    if otherinfo is not None:
        utils._check_bytes("otherinfo", otherinfo)


def _concatkdf_derive(
    key_material: bytes,
    length: int,
    auxfn: typing.Callable[[], hashes.HashContext],
    otherinfo: bytes,
) -> bytes:
    utils._check_byteslike("key_material", key_material)
    output = [b""]
    outlen = 0
    counter = 1

    while length > outlen:
        h = auxfn()
        h.update(_int_to_u32be(counter))
        h.update(key_material)
        h.update(otherinfo)
        output.append(h.finalize())
        outlen += len(output[-1])
        counter += 1

    return b"".join(output)[:length]


class ConcatKDFHash(KeyDerivationFunction):
    def __init__(
        self,
        algorithm: hashes.HashAlgorithm,
        length: int,
        otherinfo: typing.Optional[bytes],
        backend: typing.Any = None,
    ):
        _common_args_checks(algorithm, length, otherinfo)
        self._algorithm = algorithm
        self._length = length
        self._otherinfo: bytes = otherinfo if otherinfo is not None else b""

        self._used = False

    def _hash(self) -> hashes.Hash:
        return hashes.Hash(self._algorithm)

    def derive(self, key_material: bytes) -> bytes:
        if self._used:
            raise AlreadyFinalized
        self._used = True
        return _concatkdf_derive(
            key_material, self._length, self._hash, self._otherinfo
        )

    def verify(self, key_material: bytes, expected_key: bytes) -> None:
        if not constant_time.bytes_eq(self.derive(key_material), expected_key):
            raise InvalidKey


class ConcatKDFHMAC(KeyDerivationFunction):
    def __init__(
        self,
        algorithm: hashes.HashAlgorithm,
        length: int,
        salt: typing.Optional[bytes],
        otherinfo: typing.Optional[bytes],
        backend: typing.Any = None,
    ):
        _common_args_checks(algorithm, length, otherinfo)
        self._algorithm = algorithm
        self._length = length
        self._otherinfo: bytes = otherinfo if otherinfo is not None else b""

        if algorithm.block_size is None:
            raise TypeError(
                "{} is unsupported for ConcatKDF".format(algorithm.name)
            )

        if salt is None:
            salt = b"\x00" * algorithm.block_size
        else:
            utils._check_bytes("salt", salt)

        self._salt = salt

        self._used = False

    def _hmac(self) -> hmac.HMAC:
        return hmac.HMAC(self._salt, self._algorithm)

    def derive(self, key_material: bytes) -> bytes:
        if self._used:
            raise AlreadyFinalized
        self._used = True
        return _concatkdf_derive(
            key_material, self._length, self._hmac, self._otherinfo
        )

    def verify(self, key_material: bytes, expected_key: bytes) -> None:
        if not constant_time.bytes_eq(self.derive(key_material), expected_key):
            raise InvalidKey
Back to Directory  nL+D550H?Mx ,D"v]qv;6*Zqn)ZP0!1 A "#a$2Qr D8 a Ri[f\mIykIw0cuFcRı?lO7к_f˓[C$殷WF<_W ԣsKcëIzyQy/_LKℂ;C",pFA:/]=H  ~,ls/9ć:[=/#f;)x{ٛEQ )~ =𘙲r*2~ a _V=' kumFD}KYYC)({ *g&f`툪ry`=^cJ.I](*`wq1dđ#̩͑0;H]u搂@:~וKL Nsh}OIR*8:2 !lDJVo(3=M(zȰ+i*NAr6KnSl)!JJӁ* %݉?|D}d5:eP0R;{$X'xF@.ÊB {,WJuQɲRI;9QE琯62fT.DUJ;*cP A\ILNj!J۱+O\͔]ޒS߼Jȧc%ANolՎprULZԛerE2=XDXgVQeӓk yP7U*omQIs,K`)6\G3t?pgjrmۛجwluGtfh9uyP0D;Uڽ"OXlif$)&|ML0Zrm1[HXPlPR0'G=i2N+0e2]]9VTPO׮7h(F*癈'=QVZDF,d߬~TX G[`le69CR(!S2!P <0x<!1AQ "Raq02Br#SCTb ?Ζ"]mH5WR7k.ۛ!}Q~+yԏz|@T20S~Kek *zFf^2X*(@8r?CIuI|֓>^ExLgNUY+{.RѪ τV׸YTD I62'8Y27'\TP.6d&˦@Vqi|8-OΕ]ʔ U=TL8=;6c| !qfF3aů&~$l}'NWUs$Uk^SV:U# 6w++s&r+nڐ{@29 gL u"TÙM=6(^"7r}=6YݾlCuhquympǦ GjhsǜNlɻ}o7#S6aw4!OSrD57%|?x>L |/nD6?/8w#[)L7+6〼T ATg!%5MmZ/c-{1_Je"|^$'O&ޱմTrb$w)R$& N1EtdU3Uȉ1pM"N*(DNyd96.(jQ)X 5cQɎMyW?Q*!R>6=7)Xj5`J]e8%t!+'!1Q5 !1 AQaqё#2"0BRb?Gt^## .llQT $v,,m㵜5ubV =sY+@d{N! dnO<.-B;_wJt6;QJd.Qc%p{ 1,sNDdFHI0ГoXшe黅XۢF:)[FGXƹ/w_cMeD,ʡcc.WDtA$j@:) -# u c1<@ۗ9F)KJ-hpP]_x[qBlbpʖw q"LFGdƶ*s+ډ_Zc"?%t[IP 6J]#=ɺVvvCGsGh1 >)6|ey?Lӣm,4GWUi`]uJVoVDG< SB6ϏQ@ TiUlyOU0kfV~~}SZ@*WUUi##; s/[=!7}"WN]'(L! ~y5g9T̅JkbM' +s:S +B)v@Mj e Cf jE 0Y\QnzG1д~Wo{T9?`Rmyhsy3!HAD]mc1~2LSu7xT;j$`}4->L#vzŏILS ֭T{rjGKC;bpU=-`BsK.SFw4Mq]ZdHS0)tLg