diff --git a/apps/iot/src/iot_cipher_aes.erl b/apps/iot/src/iot_cipher_aes.erl
index 005c5a9..4941134 100644
--- a/apps/iot/src/iot_cipher_aes.erl
+++ b/apps/iot/src/iot_cipher_aes.erl
@@ -22,7 +22,7 @@ test() ->
 
 %% 基于aes的加密算法, aes_256_cbc
 -spec encrypt(binary(), binary()) -> binary().
-encrypt(Key, PlainText) when is_binary(Key), is_binary(PlainText), byte_size(PlainText) >= 32 ->
+encrypt(Key, PlainText) when is_binary(Key), is_binary(PlainText) ->
     IV = binary:part(Key, {0, 16}),
     crypto:crypto_one_time(aes_256_cbc, Key, IV, PlainText, [{encrypt, true}, {padding, pkcs_padding}]).