make messageheader a dataclass

messenger.py

@@ -2,6 +2,8 @@ import os
 import pickle
 import string
 import hmac
+from dataclasses import dataclass
+
 from cryptography.hazmat.primitives import hashes, serialization
 from cryptography.hazmat.primitives.asymmetric import ec
 from cryptography.hazmat.primitives.ciphers.aead import AESGCM
@@ -9,6 +11,7 @@ from cryptography.hazmat.primitives.kdf.hkdf import HKDF
 
 CURVE = ec.SECP256R1()
 
+@dataclass
 class MessageHeader:
     dh: object
     pn: int
@@ -29,7 +32,6 @@ def KDF_RK(rk, dh_out):
     ).derive(dh_out)
     return output[:32], output[32:]
 
-
 def KDF_CK(ck):
     return (
         hmac.new(ck, b"\x01", "sha256").digest(),
@@ -40,7 +42,6 @@ def ENCRYPT(mk, plaintext, associated_data):
     nonce = os.urandom(12)
     return nonce + AESGCM(mk).encrypt(nonce, plaintext, associated_data)
 
-
 def DECRYPT(mk, ciphertext, associated_data):
     return AESGCM(mk).decrypt(ciphertext[:12], ciphertext[12:], associated_data)