Original text:
3.1. The EDHOC protocol consists of three mandatory messages (message_1, <del> message_2, message_3) between Initiator and Responder, an optional fourth message (message_4), and an error message.  All EDHOC messages are CBOR Sequences RFC8742, and are deterministically encoded. fig- flow illustrates an EDHOC message flow with the optional fourth message as well as the content of each message.  The protocol </del>  elements in the figure are introduced in overview and asym.  Message formatting and processing are specified in asym and error.

Reviewer comments:
URL I have been reading v17 and sent some comments to the authors, that I summarize here: 1) - Regarding RPK, previous versions of the document had a more detailed explanation about RPK. For example, in version v06 you had "The Initiator and the Responder MAY use different types of credentials, e.g. one uses an RPK and the other uses a public key certificate.” So RPK is included as part of the definition of authentication credential. However, v17 may have a different meaning since it seems “credentials" is defined as follows: "EDHOC relies on COSE for identification of credentials (see Section 3.5.3), for example X.509 certificates [RFC5280], C509 certificates [I-D.ietf-cose-cbor-encoded-cert], CWTs [RFC8392] and CWT Claims Sets (CCS) [RFC8392]. When the identified credential is a chain or a bag, the authentication credential CRED_x is just the end entity X.509 or C509 certificate / CWT. I assume RPK is also an authentication credential and this should be included in this text. A clarification would be worthy. 2) I assume it is possible that any two IoT devices can act as initiator but also as a responder, even between same two peers. It is the application which decides when to start EDHOC (initiator) in a particular case, correct? 3) It seems the EDHOC does not define any exchange for the key update (some sort of rekey). It seems an application at some point exchange some messages as "some event that triggered the key update.” Then the application call to EDHOC-KeyUpdate function to get a new PRK. Am I right? I am asking because looking at IKEv2, for example, and for the rekey, an exchange is required. Although it would add a little bit more complexity, wouldn’t it be sensical that EDHOC defines a 1 RTT to exchange a couple of nonces for the rekeying. Moreover, this function is defined in an Appendix. Is it mandatory to implement?
Yes. The document should talk about RPK a bit more as that is term that people might search for. Should be explained that CWT is the format EDHOC uses for raw public keys (RPK). Hi all: I have been reading v17 and sent some comments to the authors, that I summarize here: 1) - Regarding RPK, previous versions of the document had a more detailed explanation about RPK. For example, in version v06 you had "The Initiator and the Responder MAY use different types of credentials, e.g. one uses an RPK and the other uses a public key certificate.” So RPK is included as part of the definition of authentication credential. However, v17 may have a different meaning since it seems “credentials" is defined as follows: "EDHOC relies on COSE for identification of credentials (see Section 3.5.3), for example X.509 certificates [RFC5280], C509 certificates [I-D.ietf-cose-cbor-encoded-cert], CWTs [RFC8392] and CWT Claims Sets (CCS) [RFC8392]. When the identified credential is a chain or a bag, the authentication credential CRED_x is just the end entity X.509 or C509 certificate / CWT. I assume RPK is also an authentication credential and this should be included in this text. A clarification would be worthy. 2) I assume it is possible that any two IoT devices can act as initiator but also as a responder, even between same two peers. It is the application which decides when to start EDHOC (initiator) in a particular case, correct? 3) It seems the EDHOC does not define any exchange for the key update (some sort of rekey). It seems an application at some point exchange some messages as "some event that triggered the key update.” Then the application call to EDHOC-KeyUpdate function to get a new PRK. Am I right? I am asking because looking at IKEv2, for example, and for the rekey, an exchange is required. Although it would add a little bit more complexity, wouldn’t it be sensical that EDHOC defines a 1 RTT to exchange a couple of nonces for the rekeying. Moreover, this function is defined in an Appendix. Is it mandatory to implement? Beyond these clarifications, I think the document is ready. Best Regards. Rafa Marin-Lopez, PhD Dept. Information and Communications Engineering (DIIC) Faculty of Computer Science-University of Murcia 30100 Murcia - Spain Telf: +34868888501 Fax: +34868884151 e-mail: EMAIL

Revised text:
3.1. The EDHOC protocol consists of three mandatory messages (message_1,  <ins> message_2, message_3) between an Initiator and a Responder, an optional fourth message (message_4), and an error message.  The roles have slightly different security properties which should be considered when the roles are assigned, see sec-prop.  All EDHOC messages are CBOR Sequences RFC8742, and are deterministically encoded. fig-flow illustrates an EDHOC message flow with the optional fourth message as well as the content of each message.  The protocol </ins> elements in the figure are introduced in overview and asym.  Message formatting and processing are specified in asym and error.