I have reviewed this document as part of the security directorate's 
ongoing effort to review all IETF documents being processed by the 
IESG.  These comments were written primarily for the benefit of the 
security area directors.  Document editors and WG chairs should treat 
these comments just like any other last call comments.

   This document defines the syntax for private key information and a 
   content type for it.  Private-key information includes a private key 
   for a specified public-key algorithm and a set of attributes. The 
   Cryptographic Message Syntax (CMS), as defined in RFC 5652, can be 
   used to digitally sign, digest, authenticate, or encrypt the 
   asymmetric key format content type.  This document obsoletes RFC 
   5208. 

In particular this document describes extensions to existing protocols
to encode and transfer public and private asymmetric key information.
I find no additional issues with this document.

-derek
-- 
       Derek Atkins                 617-623-3745
       derek at ihtfp.com             www.ihtfp.com
       Computer and Internet Security Consultant