Subject: [core] Rekeying of OSCORE

From: Göran Selander <[email-masked]>
Date: Tue, 10 Nov 2020 17:16:30 +0000

All,

There is ongoing work in CFRG on usage limits of AEAD algorithms [1]. Thomas already raised the question what is the impact on OSCORE [2]. A related discussion has now started om the LAKE GIthub [3].

There are at least two different aspects:

  1.  What is the acceptable probability for IoT? This relates to adapt the assumptions of the CFRG document to the IoT setting. There is to my knowledge no activity on this aspect.

  1.  How can we do this rekeying for OSCORE? As discussed in [3] there may be advantages making additions to OSCORE (rather than EDHOC) to allow rekeying as part of OSCORE processing. Should we allocate a little time at IETF 109 to discuss this?

(Items 1 & 2 are independent. With a solution to 2, this may be used with the bounds of [1], potentially leading to too frequent rekeying but on the safe side.)

Göran

[1] https://tools.ietf.org/html/draft-irtf-cfrg-aead-limits
[2] https://mailarchive.ietf.org/arch/msg/core/rK96-Dsyhl4EmtJpOriYEENLs0g/
[3] https://github.com/lake-wg/edhoc/issues/20