Re: [Rats] About (E)UID's

Henk Birkholz <henk.birkholz@sit.fraunhofer.de> Wed, 12 February 2020 16:01 UTC

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From: Henk Birkholz <henk.birkholz@sit.fraunhofer.de>
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Date: Wed, 12 Feb 2020 11:01:08 -0500
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Subject: Re: [Rats] About (E)UID's
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The security of the RATS architecture does not rely on a single claim. 
It relies in trust anchors that you can put trust into in order to 
believe a certification path and therefore attestation provenance, it 
also relies an Endorsements provided by potential several Supply Chain 
entities.

A single UEID claim that could encounter a collision (maliciously 
intended or by accident) will not necessarily compromise a complete 
instance of a remote attestation procedures. If your Claim set and 
corresponding secret/shielded key material are sparse, this reduces the 
believability of the corresponding evidence and therefore lower the 
level of assurance/security of that implemented RATS architecture.

But that is an implementation choice. The architecture offers suitable 
set of secure methods. If base all you post-process decision, than that 
is a choice and should be aware of the risk involved for not using any 
other secure methods.

Viele Grüße,

Henk

On 12.02.20 10:49, Salz, Rich wrote:
> I am still concerned about what fails if someone re-uses an EUID, either 
> by accident or maliciously.  If the security of the RATS architecture 
> depends on uniqueness, this seems important.
> 
> 
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