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

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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