Initial commit

custom_components/plejd/pyplejd/crypto.py

@@ -0,0 +1,29 @@
+import hashlib
+import struct
+
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+
+def encrypt_decrypt(key, addr, data):
+    buf = addr + addr + addr[:4]
+
+    ct = Cipher(
+            algorithms.AES(bytearray(key)),
+            modes.ECB(),
+            backend=default_backend()
+        )
+    ct = ct.encryptor()
+    ct = ct.update(buf)
+
+    output = b""
+    for i,d in enumerate(data):
+        output += struct.pack("B", d^ct[i%16])
+    return output
+
+def auth_response(key, challenge):
+    k = int.from_bytes(key, "big")
+    c = int.from_bytes(challenge, "big")
+    intermediate = hashlib.sha256((k^c).to_bytes(16, "big")).digest()
+    part1 = intermediate[:16]
+    part2 = intermediate[16:]
+    return bytearray([(a^b) for (a,b) in zip(part1, part2)])