Added libs

fspn/utils/aes_util.py

@@ -0,0 +1,17 @@
+from Crypto.Cipher import AES
+
+def encrypt(data:bytes, key:bytes):
+    cipher = AES.new(key, AES.MODE_EAX)
+    nonce = cipher.nonce
+    ciphertext, mac = cipher.encrypt_and_digest(data)
+    return nonce, ciphertext, mac
+
+def decrypt_and_verify(nonce:bytes, data:bytes, mac:bytes, key:bytes):
+    cipher = AES.new(key, AES.MODE_EAX, nonce=nonce)
+    plaintext = cipher.decrypt(data)
+    try:
+        cipher.verify(mac)
+    except ValueError:
+        return None
+    return plaintext
+