Secure Communication Scheme - Libelium Waspmote v15 and Plug & Sense Programming Manual

5. Secure Communication Scheme

It is possible to communicate from Waspmote to Meshlium directly using secure communication schemes.
In the case that XBee modules are used to communicate, the user has the chance to enable the AES-128 link layer encryption
that these modules provide. On the other hand, application layer encryption can be used thanks to the AES encryption libraries.
This second option is available for any kind of communication module provided by Waspmote (XBees, LoRa, 3G, GPRS, WiFi,
Bluetooth, BLE, Industrial Protocols, etc). The API libraries permit to use AES encryption with different key sizes: 128, 192 or 256
bits.
The following diagram shows how the communication scheme works:
Figure : Communication scheme
The user has three different possibilities: AES-128, AES-192 and AES-256. Regarding the cipher block mode, only ECB is supported
to communicate to Meshlium. Besides, zeros padding is the only choice permitted.
The process of how to encrypt a previously created frame is as follows:
1. Create a new Frame (ASCII or BINARY)
2. Generate an encrypted frame from the original one
3. Send the encrypted frame
For more information about how to create encrypted frames go to:
Once the encrypted frame is received by Meshlium, the sensorParser decrypts the frame and stores the sensor fields inside the
database automatically.
Example of sending encrypted frames to Meshlium via XBee-802.15.4:
http://www.libelium.com/development/waspmote/examples/aes-07-encryption-128-cbc-zeros/
Data Frame guide
-15-
Secure Communication Scheme
v7.0