Re: [Suit] draft-housley-suit-cose-hash-sig

Michael:

Thanks for reading.  I think you need to look at [HASHSIG].  It uses XDR [RFC4506] to represent the signatures.  The XXDR structures are in Section 7 of [HASHSIG].

Russ

> On Jun 13, 2018, at 2:09 PM, Michael Richardson <mcr+ietf@sandelman.ca> wrote:
> 
> 
> I have read the -01 draft today.
> I have not read [HASHSIG] yet.
> I thought I'd try reading this first, to see what questions I had.
> 
> I have implemented COSE Sign1 with ECDSA in Ruby, so I have a grasp of
> what we are trying to plug hash-sig *into*.
> 
> 
> Suggestions:
> 1) would the structure show in section 3 be easier if it was described by
>   CDDL?  I'm rather unclear about this.
> 
> 2) I din't understand section 4, where it says:
>      o  If the 'key_ops' field is present, it MUST include 'sign' when
>                 creating a hash-based signature.
> 
>      o  If the 'key_ops' field is present, it MUST include 'verify'
>                 when verifying a hash-based signature.
> 
> Clearly this is not something that travels over the network.  Is this
> somehow indicating how to understand if one is dealing a public (verify) key
> or a private (sign) key?
> 
> 3) the variations: LMS_SHA256_M32_H20, and LMOTS_SHA256_N32_W2, etc. are
>   listed, but I don't know if they need to be carried in the signature
>   structure somehow.
> 
> 4) I thought that perhaps we'd need CBOR or COSE specific way to transport
>   the signatures.  I guess I shall read HASHSIG to find out what the
>   signatures look like.
> 
> I understand draft-mcgrew-hash-sigs-11 is being advanced by CFRG.
> I believe that SUIT should adopt this document, and should do so in the
> current state.
> 
> I would like to have some examples in CBOR/COSE worked out with private keys
> available in the appendices.
> 
> --
> ]               Never tell me the odds!                 | ipv6 mesh networks [
> ]   Michael Richardson, Sandelman Software Works        | network architect  [
> ]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [
> 
> --
> Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
> -= IPv6 IoT consulting =-
> 
> 
> 
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Re: [Suit] draft-housley-suit-cose-hash-sig

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