Subject: Re: [P2PSIP] Size of Signature.algorithm and SignerIdentityValue.hash_alg

From: "Michael Chen" <[email-masked]>
Date: Tue, 12 Apr 2011 11:41:13 -0700

Marc,

> -------- Original Message --------
> Subject: Re: [P2PSIP] Size of Signature.algorithm and
> SignerIdentityValue.hash_alg
> From: Marc Petit-Huguenin <[email-masked]>
> Date: Mon, April 11, 2011 11:54 pm
> To: Michael Chen <[email-masked]>,  P2PSIP Mailing List
> <[email-masked]>
>
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Hi Michael,
>
> On 04/07/2011 06:10 PM, Michael Chen wrote:
> > Hi,
> >
> > Section 5.3.4 of the base-13 draft needs some work:
> >
> > 1) The type name SignatureAndHashAlgorithm should be renamed SignatureAlgorithm
> > to match the same name in TLS. This name caused confusion in Wireshark
> > implementation, which treats it as two bytes, one for signature algorithm and
> > one for hash algorithm.
>
> My understanding is the opposite of yours:  It's the text that is incorrect, i.e.
>
> "The algorithm definitions are found in the IANA TLS SignatureAlgorithm Registry."
>
> should be replaced by
>
> "The algorithm definitions are found in the IANA TLS SignatureAlgorithm and
> HashSignature Registries."
>
> >
> > 2) In TLS, both SignatureAlgorithm and HashAlgorithm are enum that are never
> > part of any PDU send over the wire. Therefore, their size is not relevant to the
> > TLS text. These two are in the RELOAD PDU, so this draft MUST define their size
> > explicitly to be both uint8. The value of the fields can still mention TLS.
>
> They are both defined in TLS 1.2 section 7.4.1.4.1 with a size of 8 bit [see
> RELOAD section 5.3.1.1 for the meaning of (255)]:
>
>     enum {
>           none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5),
>           sha512(6), (255)
>       } HashAlgorithm;
>
>       enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) }
>         SignatureAlgorithm;

My mistake, I was reading off an old link to the TLS 1.1 text.

--Michael