Last Call Review of draft-ietf-oauth-spop-11

Request Review of draft-ietf-oauth-spop
Requested rev. no specific revision (document currently at 15)
Type Last Call Review
Team General Area Review Team (Gen-ART) (genart)
Deadline 2015-06-01
Requested 2015-05-20
Authors Nat Sakimura, John Bradley, Naveen Agarwal
Draft last updated 2015-06-09
Completed reviews Genart Last Call review of -11 by Alexey Melnikov (diff)
Secdir Last Call review of -11 by Ben Laurie (diff)
Opsdir Last Call review of -11 by Melinda Shore (diff)
Assignment Reviewer Alexey Melnikov 
State Completed
Review review-ietf-oauth-spop-11-genart-lc-melnikov-2015-06-09
Reviewed rev. 11 (document currently at 15)
Review result Almost Ready
Review completed: 2015-06-09


I am the assigned Gen-ART reviewer for this draft. For background on
Gen-ART, please see the FAQ at

This review is in response to a request for early Gen-ART review.

Document: draft-ietf-oauth-spop-11
Reviewer: Alexey Melnikov
Review Date: 2015-06-09
IETF LC End Date: 2015-06-01
IESG Telechat date: 2015-06-11

Summary: Almost Ready

Major Concerns:

What is the justification for having the "plain" verifier? If one is 

intercepted by a malicious application, your extension becomes pointless.

Minor Concerns:

Is code_challenge_method missing in 4.5?

Sections 7.1 and 7.3 are talking about the same thing? Should they be 

merged into one? If they are not talking about the same thing, should 

they be named differently?


4.2.  Client creates the code challenge

   The client then creates a code challenge, "code_challenge", derived
   from the "code_verifier" by using one of the following
   transformations on the "code_verifier":

   plain  "code_challenge" = "code_verifier"
   S256  "code_challenge" = BASE64URL-

   It is RECOMMENDED to use the S256 transformation when possible.
   ABNF for "code_challenge" is as follows.

   code-challenge = 43*128unreserved
   unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"
   ALPHA = %x41-5A / %x61-7A
   DIGIT = %x30-39

SHA-256 requires a normative reference.