import hmac
import hashlib


# Import shared secret
with open('k', 'rb') as file:
    shared_key = file.read()

# Compute hmac
with open('mactext', 'rb') as file:
    data = file.read()

m = data[:18]
m_hash = data[18:]

hmac_oject: hmac.HMAC = hmac.new(shared_key, m, hashlib.sha256)
derived_hmac = hmac_oject.digest()
print(f'Derived HMAC: {hmac_oject.digest()}')

if derived_hmac == m_hash:
    print("HMAC matches message")

else:
    print("HMAC does not match message")