Re: Comments on XML-Signature S&P draft

In message "Re: Comments on XML-Signature S&P draft"
    on 00/10/04, "Joseph M. Reagle Jr." <reagle@w3.org> writes:
> Yes, I goofed in my scenario, I'll try again:
> 
> Author creates signature that includes a reference to KeyInfo element (it is 
> signed) in a separate document via a relative URL. The 
> CanonicalizationMethod absolutizes the URI via some arbitrary method. (Also, 
> the SignatureMethod could be changed in some way too).
> 
> The thing that's necessary is that the applications validate that which was 
> signed. So in section 3.2.2 the only thing that the applications deals with 
> is the KeyInfo (and while it need not be signed, if it is we should protect 
> it appropriately) and the SignatureMethod. If either of these could've been 
> altered by the CanonicalizationMethod, then the canonicalization step in 
> validation should correspond to the canonicalization in generation in 3.1.2.2.

I still have strangeness.  In your scenario, signature
applications can not get correct meaning of a KeyInfo only from
the KeyInfo itself.  Transformed results of Reference elements
are usually used only for digest calculation.  Signature
applications have to re-parse transformed results of KeyInfo
References, but applications can not know whether a reference
points a KeyInfo or not before re-parsing. (Note that even if
the URI attribute of a Reference element points a KeyInfo
element, transformd result would not always become a KeyInfo
element.)

-- 
TAMURA Kent @ Tokyo Research Laboratory, IBM

Received on Thursday, 5 October 2000 03:33:21 UTC