- Key derivation using the HMAC algorithm
import hashlib
import hmac, os
from math import ceil
def hmac_hash(hash_object, key, data):
return hmac.new(key, data, hash_object).digest()
def hkdf(hash_object, output_size, input_key, salt=b"", data=b""):
hash_len = hash_object().digest_size
temp = b""
output = b""
if len(salt) == 0:
salt = bytes([0] * hash_len)
key_output = hmac_hash(hash_object, salt, input_key)
for i in range(ceil(output_size / hash_len)):
temp = hmac_hash(hash_object, key_output, temp + data + bytes([1 + i]))
output += temp
return output[:output_size]
if __name__ == '__main__':
test = hkdf(hashlib.sha512, 24, os.urandom(16))
print(test.hex())