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Re: [Cfrg] [saag] Further MD5 breaks: Creating a rogue CAcertificate

2009-01-01 13:56:22

Paul Hoffman wrote:
At 3:06 PM +0000 1/1/09, Ben Laurie wrote:
Surely the whole point of DER is that there's only one correct way to
encode any particular certificate?

Not so "surely". The SEQUENCE for extensions does not say what order they 
should be in.

That doesn't change the _point_ of DER. If extensions should have been
specified as a SET but are defined as a SEQUENCE, then they are broken

So, either extensions must be sorted, or changing their order changes
their meaning. Either way, nothing can be reordered.

Wrong on both counts. Each extension has stand-alone semantics, and they can 
be in any order.

My point was about the correct use of DER. It seems extensions use it

However, this is irrelevant for the MD5 break discussion, as is clearly shown 
in the paper.

I am discussing the correct use of DER :-)


"There is no limit to what a man can do or how far he can go if he
doesn't mind who gets the credit." - Robert Woodruff

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