Message Integrity Code

What is it? 

The message integrity code (MIC) is a code that validates the integrity and authenticity of a message in a LoRaWAN® network. It is determined over specific fields in the message. Once calculated, the code is added to the message itself.  

How does it work? 

The message types for which the MIC is calculated include the following: 

• join-request 
• join-accept 
• data messages (up and down) 
• rejoin-request (Type 0, 1, 2) 

Keys used to determine the MIC are listed below: 

• Application Key (AppKey) 
• Network Session Key (NwkSKey) 
• Network Key (NwkKey) 
• JSIntKey 
• SNwkSIntKey 
• FNwkSIntKey