[thread-cert] import `Crypto` on demand (#8109)
This commit imports `Crypto` module only when it's used.
This helps thread-cert tests that do not use message factory to run
without having to install `Crypto` module.
diff --git a/tests/scripts/thread-cert/net_crypto.py b/tests/scripts/thread-cert/net_crypto.py
index 66533b9..d9d007f 100755
--- a/tests/scripts/thread-cert/net_crypto.py
+++ b/tests/scripts/thread-cert/net_crypto.py
@@ -33,8 +33,6 @@
from binascii import hexlify
-from Crypto.Cipher import AES
-
class CryptoEngine:
""" Class responsible for encryption and decryption of data. """
@@ -64,6 +62,8 @@
"""
key, nonce, auth_data = self._crypto_material_creator.create_key_and_nonce_and_authenticated_data(message_info)
+ from Crypto.Cipher import AES
+
cipher = AES.new(key, AES.MODE_CCM, nonce, mac_len=self.mic_length)
cipher.update(auth_data)
@@ -83,6 +83,8 @@
"""
key, nonce, auth_data = self._crypto_material_creator.create_key_and_nonce_and_authenticated_data(message_info)
+ from Crypto.Cipher import AES
+
cipher = AES.new(key, AES.MODE_CCM, nonce, mac_len=self.mic_length)
cipher.update(auth_data)
