Last Call Review of draft-ietf-stir-oob-05
review-ietf-stir-oob-05-genart-lc-nandakumar-2019-09-16-00

Request Review of draft-ietf-stir-oob
Requested rev. no specific revision (document currently at 06)
Type Last Call Review
Team General Area Review Team (Gen-ART) (genart)
Deadline 2019-09-17
Requested 2019-09-03
Authors Eric Rescorla, Jon Peterson
Draft last updated 2019-09-16
Completed reviews Secdir Last Call review of -05 by Watson Ladd (diff)
Genart Last Call review of -05 by Suhas Nandakumar (diff)
Opsdir Last Call review of -05 by Shwetha Bhandari (diff)
Genart Telechat review of -06 by Suhas Nandakumar
Secdir Telechat review of -06 by Watson Ladd
Assignment Reviewer Suhas Nandakumar
State Completed
Review review-ietf-stir-oob-05-genart-lc-nandakumar-2019-09-16
Posted at https://mailarchive.ietf.org/arch/msg/gen-art/40TTDHlTBecIeCRy594Y08t_AO8
Reviewed rev. 05 (document currently at 06)
Review result Almost Ready
Review completed: 2019-09-16

Review
review-ietf-stir-oob-05-genart-lc-nandakumar-2019-09-16

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

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Document: draft-ietf-stir-oob-??
Reviewer: Suhas Nandakumar
Review Date: 2019-09-16
IETF LC End Date: 2019-09-17
IESG Telechat date: Not scheduled for a telechat

Summary: Thanks for a lucid document. This document is Almost Ready with few minor issues / clarifications.

Major issues: None

Minor issues:
1. Section 7.2 para 2 states : "The CPS responds with any such PASSporTs (assuming they exist)." 
Given CPS will always respond with a dummy PASSporT, the statement in the parentheses doesn't hold.

2. Section 7.4 Call flow: "Call from CS (forged caller-id info)" . Since its the attacker making the call here, we probably need to change it as "Call from Attacker (forged caller-id info)".

3. Section 7.5 has the following: 

Sign(K_cps, K_temp)
Sign(K_temp, E(K_receiver, PASSporT)) --->

This is a clarification question for my understanding. What happens when 
one of the 2 messages sent gets lost when storing the PASSporT. Should we need to add 
any clarifications to that extent ?

4. Section 77.5 last para: clarification question
Since PASSporT is encrypted at CPS , how is it aged out based on the "iat" value. Is it 
a function to VS to age out PASSporTs at a given CPS ?


5. Section 8.2 last part has the  sentence "This document
   does not prescribe any particular treatment of calls that have valid
   PASSporTs associated with them."

 I wasn't sure of the intent of this sentence. 


Nits/editorial comments:

1. Introduction para 1: Reference to PASSporT missing
2. Introduction para 2: Xalls -> Calls
3. Section 5.2 para 1: would be nice to add reference to Section 10
4. Section 7.2 Call Flow: "Store PASSporT" --> "Store Encrypted PASSporT"
5. Section 7.2 Call Flow: "Ring phone with callerid" --> "Ring phone with verified callerid"
6. Section 8.2 Step 3: "number number" --> "number"
7. Section 8.3 para 2: "Per Step 3" --> "Per Step 3 of Section 8.1"
8. Section 10 last para: The acronyms AS and VS are used first time
9. Section 11: missing references to subcert, VIPR