mirror of
https://github.com/markqvist/Reticulum.git
synced 2024-10-01 03:15:44 -04:00
Added internal python-only HKDF
This commit is contained in:
parent
f1dcda82ac
commit
5bb510b589
35
RNS/Cryptography/HKDF.py
Normal file
35
RNS/Cryptography/HKDF.py
Normal file
@ -0,0 +1,35 @@
|
||||
import hashlib
|
||||
from math import ceil
|
||||
from RNS.Cryptography import HMAC
|
||||
|
||||
def hkdf(length=None, derive_from=None, salt=None, context=None):
|
||||
hash_len = 32
|
||||
|
||||
def hmac_sha256(key, data):
|
||||
return HMAC.new(key, data, hashlib.sha256).digest()
|
||||
|
||||
if length == None or length < 1:
|
||||
raise ValueError("Invalid output key length")
|
||||
|
||||
if derive_from == "None" or derive_from == "":
|
||||
raise ValueError("Cannot derive key from empty input material")
|
||||
|
||||
if salt == None or len(salt) == 0:
|
||||
salt = bytes([0] * hash_len)
|
||||
|
||||
if salt == None:
|
||||
salt = b""
|
||||
|
||||
if context == None:
|
||||
context = b""
|
||||
|
||||
pseudorandom_key = hmac_sha256(salt, derive_from)
|
||||
|
||||
block = b""
|
||||
derived = b""
|
||||
|
||||
for i in range(ceil(length / hash_len)):
|
||||
block = hmac_sha256(pseudorandom_key, block + context + bytes([i + 1]))
|
||||
derived += block
|
||||
|
||||
return derived[:length]
|
Loading…
Reference in New Issue
Block a user