Re: subjective names and MITM

[Adam Shostack <adam@homeport.org>]

Scott Brickner wrote:

| Adam Shostack writes:
| >	Just a minor nit regarding a well thought out post, public
| >keys are not 'global' ids, but 'system-wide' IDs.  For keys to be
| >really global, there needs to be a mechanism in place for insuring
| >that key ids are very probably unique.  One way to ensure that keys
| >are globally unique would be to integrate a KCA identifier with the
| >keyid, and KCAs base part of their reputation on not signing multiple
| >keys with the same id.
| 
| A public key *is* "very probably unique".  A "randomly selected" 1024 bit
| prime number has a specific amount of entropy in it.  The likelihood of
| two users world wide "randomly" choosing the same such prime may be
| precisely determined (assuming you can figure the entropy).

	The key does indeed have a high likelihood of being unique,
but dealing with 1024 bit identifiers could strain database systems,
especially when 100 well chosen bits would be than enough.

Adam



-- 
"It is seldom that liberty of any kind is lost all at once."
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