Module refinery.units.crypto.keyderive.hkdf

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from __future__ import annotations

from typing import Iterable

from refinery.units.crypto.keyderive import KeyDerivation


class hkdf(KeyDerivation):
    """
    HKDF key derivation as specified in RFC 5869. An extract-and-expand key derivation function used
    in TLS 1.3 and many modern protocols.
    """

    def __init__(self, size, salt, hash='SHA512'):
        super().__init__(size=size, salt=salt, hash=hash)

    def keystream(self, seed) -> Iterable[int]:
        from Cryptodome.Hash import HMAC
        hash_algorithm = self._hash_module()
        prk = HMAC.new(self.args.salt, seed, hash_algorithm).digest()
        previous = bytearray(1)
        for counter in range(1, 256):
            previous[-1] = counter
            u = HMAC.new(prk, previous, hash_algorithm)
            d = u.digest()
            yield from d
            previous[:-1] = d

Classes

class hkdf (size, salt, hash='SHA512')

HKDF key derivation as specified in RFC 5869. An extract-and-expand key derivation function used in TLS 1.3 and many modern protocols.

Expand source code Browse git 
class hkdf(KeyDerivation):
    """
    HKDF key derivation as specified in RFC 5869. An extract-and-expand key derivation function used
    in TLS 1.3 and many modern protocols.
    """

    def __init__(self, size, salt, hash='SHA512'):
        super().__init__(size=size, salt=salt, hash=hash)

    def keystream(self, seed) -> Iterable[int]:
        from Cryptodome.Hash import HMAC
        hash_algorithm = self._hash_module()
        prk = HMAC.new(self.args.salt, seed, hash_algorithm).digest()
        previous = bytearray(1)
        for counter in range(1, 256):
            previous[-1] = counter
            u = HMAC.new(prk, previous, hash_algorithm)
            d = u.digest()
            yield from d
            previous[:-1] = d

Ancestors

Subclasses

Class variables

var reverse

The type of the None singleton.

Methods

def keystream(self, seed)
Expand source code Browse git 
def keystream(self, seed) -> Iterable[int]:
    from Cryptodome.Hash import HMAC
    hash_algorithm = self._hash_module()
    prk = HMAC.new(self.args.salt, seed, hash_algorithm).digest()
    previous = bytearray(1)
    for counter in range(1, 256):
        previous[-1] = counter
        u = HMAC.new(prk, previous, hash_algorithm)
        d = u.digest()
        yield from d
        previous[:-1] = d

Inherited members