mirror of
https://github.com/dashpay/dash.git
synced 2024-12-27 04:52:59 +01:00
34 lines
953 B
Python
34 lines
953 B
Python
#!/usr/bin/env python3
|
|
# Copyright (c) 2023 The Bitcoin Core developers
|
|
# Distributed under the MIT software license, see the accompanying
|
|
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
"""Test-only HKDF-SHA256 implementation
|
|
|
|
It is designed for ease of understanding, not performance.
|
|
|
|
WARNING: This code is slow and trivially vulnerable to side channel attacks. Do not use for
|
|
anything but tests.
|
|
"""
|
|
|
|
import hashlib
|
|
import hmac
|
|
|
|
|
|
def hmac_sha256(key, data):
|
|
"""Compute HMAC-SHA256 from specified byte arrays key and data."""
|
|
return hmac.new(key, data, hashlib.sha256).digest()
|
|
|
|
|
|
def hkdf_sha256(length, ikm, salt, info):
|
|
"""Derive a key using HKDF-SHA256."""
|
|
if len(salt) == 0:
|
|
salt = bytes([0] * 32)
|
|
prk = hmac_sha256(salt, ikm)
|
|
t = b""
|
|
okm = b""
|
|
for i in range((length + 32 - 1) // 32):
|
|
t = hmac_sha256(prk, t + info + bytes([i + 1]))
|
|
okm += t
|
|
return okm[:length]
|