[TICTOC] Updated draft-ietf-tictoc-security-requirements-07

[Tal Mizrahi <[e-mail]>]

Hi,

I have posted an updated draft.
http://tools.ietf.org/html/draft-ietf-tictoc-security-requirements-07


The most notable changes in this draft:

1.       I updated the draft to address comments from Shawn, the appointed secdir reviewer:
http://www.ietf.org/mail-archive/web/secdir/current/msg04315.html

2.       I updated the draft to address comments from Russell Smiley:
http://www.ietf.org/mail-archive/web/tictoc/current/msg01387.html
This includes:
- In section 5.1.3 and 5.1.4 we decoupled the authentication and authorization requirements. The authentication requirement level was changed to 'MUST' following the good observation made by Russell: "Absence of authentication of slaves may enable MITM attacks delaying delay_req packets and thereby distorting the delay_req packet arrival times and subsequent departure of delay_resp. The resulting asymmetry could distort the subsequent slave clock offset calculations."
- The authorization requirement remains 'MAY' for sections 5.1.3 and 5.1.4.

3.       The requirement level of section 5.8 was changed to 'MUST'. The background is the insight that MITM attacks (sections 3.2.5, 3.2.6) have the same impact and level of difficulty to implement as manipulation attacks (section 3.2.1). Hence, a similar requirement level is called for in the two cases.
Section 5.8 also clarifies that: "While the security mechanism should support the ability to detect delay attacks, it is noted that in some networks it is not possible to provide the redundancy needed for such a detection mechanism."

4.       Section 5.2: merged the two sub-requirements to a single requirement for integrity protection. The previous phrasing called for hop-by-hop integrity protection as a MUST and end-to-end as a SHOULD, but some of the feedback we received was that in some scenarios or network topologies an end-to-end may provide a higher level of security. The current phrasing just presents the tradeoff between peer-to-peer and end-to-end.

Please let me know if there are any comments.

Thanks,
Tal.