Subject: [COSE] RSA Algorithm Decisions

From: "Jim Schaad" <[email-masked]>
Date: Thu, 30 Jul 2015 15:32:25 -0700

I am currently in the process of updating/expanding the text for RSA.  This
message is what I am using the control the decision process.

*  The world of IoT is not interested (or so close to not interested) in
using RSA that it could be ignored from that point of view.  Therefore RSA
is being included as for completeness as anything else.   There may be some
other items that port over and use RSA, but it is expected that most are
going to use EC instead.

*  There is no legacy that needs to be supported for COSE.   This means that
there is no pressing need to support any of the RSA v1.5 algorithms.  Any
code that needs to have RSA can use the "modern" versions.

*  We do want to support both public keys and private keys in the COSE key
structure.  

*  There is sufficient reason to support all three if the "standard" SHA-2
hash algorithms with all of the RSA algorithms.  This means that PSS and
OAEP for SHA-256, SHA-384 and SHA-512.

*  As IoT does not have an interest in these algorithms, there is no reason
to waste precious one byte algorithm identifiers on them.  They will get two
byte algorithm identifiers.

If anyone has problems with this, please let me know.

Jim