Libelium Waspmote v15 and Plug & Sense Programming Manual page 19

Key Management on Meshlium
The AES secret key is necessary to recognize the frames sent each Waspmote to Meshlium.
Figure : Waspmote to Meshlium with AES 256
When an encrypted frame arrives to Meshlium, the sensorParser will consult the encryptionKey file for the AES secret key, and
use the AES algorithm to decrypt the message.
-19- v7.0