According to https://datatracker.ietf.org/doc/html/rfc8613#appendix-B.1, there is no need to execute echo challenge for fresh EDHOC sessions. Also, prior to this PR, fresh_master_secret_salt flag determined not only the freshness of the context, but also whether it can be stored in NVM or not. These aspects are independent of each other, as the user might need (for example):
to have different sessions stored in NVM, but also having the ability to create a new one with EDHOC,
to create a new EDHOC session on the run, and store it in NVM for future use,
to completely disable NVM support if only fresh EDHOC sessions are used.
Changes introduced:
NVM support is now configurable with a compile flag OSCORE_NVM_SUPPORT, regardless of fresh_master_secret_salt which is only applicable for a single context rather than the whole project.
Makefiles and readme were updated accordingly (NVM support enabled by default)
Integration test update (because of PIV value change) and small refactor
Fixed potential bug related to wrong parsing of PIV to SSN in some platforms.
According to https://datatracker.ietf.org/doc/html/rfc8613#appendix-B.1, there is no need to execute echo challenge for fresh EDHOC sessions. Also, prior to this PR,
fresh_master_secret_saltflag determined not only the freshness of the context, but also whether it can be stored in NVM or not. These aspects are independent of each other, as the user might need (for example):Changes introduced:
OSCORE_NVM_SUPPORT, regardless offresh_master_secret_saltwhich is only applicable for a single context rather than the whole project.