Distribution of Software Updates with End-to-End Secure Group Communication and Block-Wise Transfer for CoAP

This document defines a method for efficiently distributing a software update to multiple target devices, by using end-to-end secure group communication over UDP and IP multicast. To this end, the defined method relies on a number of building blocks developed in the Constrained RESTful Environments (CoRE) Working Group of the IETF. Those especially include the Constrained Application Protocol (CoAP), Block-wise transfers for CoAP, and the end-to-end security protocol Group Object Security for Constrained RESTful Environments (Group OSCORE). The method defined in this document is compatible with (but not dependent on) the architecture for software and firmware update developed in the Software Updates for Internet of Things (SUIT) Working Group of the IETF.