Re: Ideas/solutions to caching identical objects ...

From: George Michaelson <>
Date: Mon, 02 Dec 1996 14:31:51 +1000

I raised this question on the nlanr cache list a few months back. The answer
then was to wait for the MD5 hash signing code to be stable, and then use
this to verify documents in transit by some logic comparing URL, MD5 hash
and some level of document meta-information. (for MD5 read whatever hash
is decided on, hopefully cheap to compute)

You need the hash, and in-doc meta info since the URL may vary across different
mirror instances. Once there is something like a URN inside a document then
you have a version-specific field to compare with a hash function and a URL.

Actually, I guess you could use the URN if it was trustably globally unique but
a hash seems safer.


George Michaelson         | pty/ltd
Email: |  c/o AAPT,
Phone: +61 7 3834 9976    |  level 8, the Riverside Centre,
  Fax: +61 7 3834 9908    |  123 Eagle St, Brisbane QLD 4000
Received on Sun Dec 01 1996 - 20:38:18 MST

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