Early Review of draft-ietf-rtgwg-yang-key-chain-13

Request Review of draft-ietf-rtgwg-yang-key-chain-13
Requested rev. 13 (document currently at 24)
Type Early Review
Team YANG Doctors (yangdoctors)
Deadline 2017-02-17
Requested 2017-02-07
Requested by Mehmet Ersue
Other Reviews Rtgdir Early review of -02 by Ines Robles (diff)
Genart Last Call review of -17 by Matthew Miller (diff)
Secdir Last Call review of -17 by Vincent Roca (diff)
Genart Telechat review of -20 by Matthew Miller (diff)
Review State Completed
Reviewer Ladislav Lhotka
Review review-ietf-rtgwg-yang-key-chain-13-yangdoctors-early-lhotka-2017-02-20
Posted at https://mailarchive.ietf.org/arch/msg/yang-doctors/6U_YGi5c7U2JqxjEwvhKGdiS6wU
Reviewed rev. 13 (document currently at 24)
Review result Almost Ready
Last updated 2017-02-20


# General Comments

## Cryptographic algorithm types

What is the reason for representing these as a YANG choice with empty leaves? I think it would be more natural to use a single leaf, either an enumeration or (if extensibility is important) identityref.

## Reusability

The module defines key-chain as a grouping with the aim of making it reusable in other modules. However, this approach has known problems that are discussed in draft-ietf-netmod-schema-mount. I am not sure how relevant they are in this case but, for one, the "key-chain-ref" type is not applicable if the "key-chain" grouping is used in another module. An alternative is not to use the grouping and rely on schema mount.

## Key string style

The difference between ASCII and hexadecimal formats of key strings should be explained. I understand that the latter is a hash of the key and, if so, I'd suggest to include "hexadecimal-string" also in state data.

Also, I believe that storing clear-text key in configuration is insecure and Security Considerations should warn against it.

## Example

It might be useful to include an appendix with example instance data.

# Specific comments
## Sec. 2

-   paragraph 2: s/where ever/wherever/

## Sec. 3

-   paragraph 1: replace both Key-Id a Key-ID with Key ID (the latter is used in other places of the 
-   paragraph 2: the suggested way of supporting asymmetric keys looks like a hack, I would suggest 
    a more explicit representation, e.g. using a choice.

## Sec. 4

-   The module has inconsistent indentation: up to "grouping crypto-algorithm-types", top-level      
    statements are indented with four spaces, the subsequent ones with five spaces.

## Sec. 6

-   The statement "Given that the key chains themselves are sensitive data, it is RECOMMENDED    
    that the NETCONF communication channel be encrypted." is misleading because RFC 6241 
    requires that transport protocols for NETCONF guarantee confidentiality (and RFC 8040 does the 
    same for RESTCONF).