[cap-talk] "Secure Bookmark" terminology and Phoolproof Phishing Preventing from CMU

[David Hopwood]

Mark S. Miller wrote:
> Petnames and nicknames are both human meaningful.
> 
> Petnames are context dependent -- Alice and Bob may each have their own 
> petname for Carol, perhaps "Mom" and "Honey" respectively, and are chosen by 
> them. Carol's nickname is the name she says she goes by, perhaps "Carol". 
> Carol's nickname is context-free -- as in when she makes her choice of "Carol" 
> public.
> 
> Petnames are securely collision free -- Alice maintains her own petname 
> mapping so that only Carol is listed as her "Mom". OTOH, many people may 
> choose the nickname "Carol", so they are not collision-free.
> 
> Nicknames are useful for discovery, as when you google for "Don" (try it). 
> Alan's Client Utility used nicknames for discovery. Once introduced by a 
> discovery service to an entity allegedly with the nickname "Don", you can 
> determine if this is indeed the nickname of the entity you've been introduced 
> to by asking it "Do you go by Don?". A "yes" authenticates the nickname, since 
> a nickname as designator cannot provide any further assurance.

More precisely: you establish a secure channel to the endpoint and the
cryptographic identity provided by the discovery service. Then you ask
"Do you go by Don?" over that channel. A "yes" associates the channel and
the cryptographic identity with the nickname.

> However, once 
> discovered, you can corroborate the discovery by trying to find a petname path 
> from yourself to the same entity (such as "Stanford's Don"), at which point 
> you have some assurance about who or what you've discovered.

If the user then chooses to assign a petname to the channel, you establish a
binding between that petname and the cryptographic identity in the user's
petname directory.

-- 
David Hopwood <david.nospam.hopwood at blueyonder.co.uk>