From: Charles Lindsey (chl@clw.cs.man.ac.uk)
Date: Tue Oct 16 2001 - 04:35:54 CDT
In <20011015122523.B10181@main.templetons.com> Brad Templeton <brad@templetons.com> writes:
>On Mon, Oct 15, 2001 at 09:29:14AM +0000, Charles Lindsey wrote:
>> In <200110121025.6kp6@message-id.pfm-mainz.de> rbabel@babylon.pfm-mainz.de (Ralph Babel) writes:
>>
>> >Sign your articles. Then there's
>> >no need to cancel forgeries later.
>>
>> But then every Usenet poster worldwide needs a readily-accessible public
>> key, which is an order of magnitude worse that Brad's idea that every
>> injecting site needs one, which is iself a couple of orders of magnitude
>> worse than what we actually want.
>I'm afraid there are a couple of key misunderstandings in this comment.
>1) I have not proposed that every injecting site need a key, nor every
>user need a key for USENET in general.
You have stated that every injecting site should be able to cancel any
article injected through it. You have resisted suggestions that this
should be done by means of Cancel-Locks.
Ergo, every injecting site needs its own public key.
I grant you that the need for every individual user to have a key arose
from Ralph's impractical suggestion, and not from you.
>2) In a misunderstanding you continue to make, there is no difference
>in a certificate system between a few keys and a billion. ...
The depth of the tree of certicifactes is proportional to the logarithm of
the total number of keys involved. The breadth of the tree (actually, a
directed graph) is hard to quantify (how many top-level trusted parties
are needed?), but may be linear in that number. The size of the databases
kept by the certificate authorities worldwide is certainly at least
linear. With a billion keys ... ?
But with a few hundred keys needed for newgroupers, cancellers and
moderators it is manageable. But then so is a distributed database.
-- Charles H. Lindsey ---------At Home, doing my own thing------------------------ Tel: +44 161 436 6131 Fax: +44 161 436 6133 Web: http://www.cs.man.ac.uk/~chl Email: chl@clw.cs.man.ac.uk Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K. PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5