Re: [Atoca] Requirement for Originator Authentication?

["Thomson, Martin" <[e-mail]>]

On 2011-01-16 at 06:30:33, Hannes Tschofenig wrote:
> Igor raised an interesting question during the meeting in context of
> the security threats, namely:
> 
> " Do we have the requirement to authenticate the originator? "

The question that I heard was not so much related to authentication as it was to authorization.  There was also a question about whether authentication was identity-based or on some other property, like some asserted trait.

What statements can we make about how recipients (and relays) authorize the receipt (and sending) of alert messages?
 
> I couldn't provide him an answer during the meeting because I was not
> quite sure whether he was asking the question in the style of
> 
> "Do we need end-to-end security or is a hop-by-hop security solution
> good enough?"

In the context of this interpretation, I think that there's a real need to delegate alert distribution.  The scale of distribution makes intermediaries a valuable addition.  Relying on the integrity of relays makes the authorization question more difficult to resolve.

For something concrete, the relay case is probably the simplest.  I might trust my signalling peer to a certain extent.  I certainly don't trust them enough to generate the massive packet storm requested by an alert message.  They might say the alert comes from the government, but I might require better proof than their say-so alone.  Distributing an alert will cost me money and I want proof.

That's one argument.  The other argument says that peering relationships require a degree of trust that would not be broken without serious ramifications - enough to discourage its abuse.

The recipient case might have some interesting quirks.  Particularly in wholesale/reseller arrangements.  A recipient that relies on hop-by-hop might receive an alert from the network operator: an entity with whom they have no direct relationship.  For instance, no fewer than two different operators are involved in getting packets to my house, neither of which I have a business relationship with.  How would someone - ignorant of the convoluted business arrangements that underpin their Internet service - decide to authorize an alert that is relayed by either party?

--Martin