implement DH and report functions

messenger.py

@@ -11,6 +11,9 @@ CURVE = ec.SECP256R1()
 def GENERATE_DH():
     return ec.generate_private_key(CURVE)
 
+def DH(dh_pair, dh_pub):
+    return dh_pair.exchange(ec.ECDH(), dh_pub)
+
 class MessengerServer:
     def __init__(self, server_signing_key, server_decryption_key):
         self.server_signing_key = server_signing_key
@@ -54,5 +57,28 @@ class MessengerClient:
         return
 
     def report(self, name, message):
-        raise Exception("not implemented!")
-        return
+        report = (name, message)
+        plaintext = pickle.dumps(report)
+        temp_key = GENERATE_DH()
+        temp_bytes = temp_key.public_key().public_bytes(
+            serialization.Encoding.X962,
+            serialization.PublicFormat.UncompressedPoint,
+        )
+        shared_secret = DH(temp_key, self.server_encryption_pk)
+        hkdf = HKDF(
+            algorithm=hashes.SHA256(),
+            length=32,
+            salt=None,
+            info=b""
+        )
+        key = hkdf.derive(shared_secret)
+        nonce = os.urandom(12)
+        aesgcm = AESGCM(key)
+        ciphertext = aesgcm.encrypt(nonce, plaintext, temp_bytes) # not sure if passing in temp_bytes is correct, but it seems like it should be
+        data = {
+            "bytes": temp_bytes,
+            "nonce": nonce,
+            "ciphertext": ciphertext
+        }
+        return plaintext.decode("latin1"), pickle.dumps(data)
+