M2M eSIMs are defined by GSMA documents SGP.01 and SGP.02. SGP.01 is a functional specification while SGP.02 defines the technical realisation of the functional spec. Within the GSMA SGP.01 is defined by the GSMA member operators ( MNO’s ), while the OEMs are tasked with producing SGP.02 which is the technical implementation specification.
Most M2M eUICC’s currently in the field comply with version 3.1 of SGP.02.
The figure below describes the basic architecture used for M2M eSIMs.
An SM-SR is responsible for establishing a secure programming channel to the eUICC while an SM-DP manipulates and personalises the Profile that is provided by the MNO into a suitable format for download. Certificates loaded into each component above and issued by a trusted Certificate Issuer ensures that the whole process is secure.
There are two distinct kinds of profile in the eUICC. The provisioning profile provides default connectivity so that the eUICC can be bootstrapped into full functionality by downloading an operational profile.
Further information about M2M eSIMs can be found on the GSMA web site.