Sum legl trubs wid TOR en France + more
2600denver at gmail.com
Sun May 14 21:10:34 UTC 2006
I agree with you about the hops. Thanks for posting the info about hard
drives. I had no idea.
On Sun May 14 21:58:42 2006, crackedactor at supanet.com <
crackedactor at supanet.com> wrote:
> Hard Disks.. (so abou the length)
> It is possible to find old data on "scrubbed" disks even with 100's of
> cycles of writeover.
> The reason is coz of wobble or track shape. Imagine washing machine at
> home, as it spins it wobbles. Now look at your hard disk (get an old one out
> that is past it and open it up!) you'll see the disk rotates at high speed.
> Thoughout its life it has a wobble, just a small one. But this wobble
> changes now and then with time. So when your write/read head lays down its
> magnetic bits on a track it does so with a wobble in it. The track itself is
> wider than the individual bit patterns and so there is only partial overlap
> with past bit patterns. When a disk finds a bits pattern which is wrong
> (from the extra data it stores for check bits) and it cant recover
> logically the original pattern it starts to "wipe" away the edges of the bit
> pattern on the track, so as to "clean" the signal. It does this by
> offsetting the head from the current midpoint of the track. It then tries a
> RE-READ the cleaned track. This is often susuccessful in removing "noise"
> from past bit patterns so as to ge
> t "clean" read of the last bit pattern. If not successful this process
> might be done any number of times upto the maximum "re-reads" specifed in
> the disk firmware.
> It is this EXTRA width and the varying wobble that allows data to be left
> on the disk even if "military strength" scrubbing is perfomed by software.
> This is particularly relevant ot data put on when the disk is young
> remaining there for some months so that the disks bearing wear changes the
> wobble. New bit patterns written over this old bit pattern are almost
> vertaain to bew able to be read - even years later!
> The more..
> A while back it was asked if "3 hops is enough". At the time I had prblems
> getting to my email account so here's my 2 cents.
> The current set 3 hops is a predictable number of hops and because of
> that, the predictability is a DEFINITE weakness in TOR.
> Its all about ENTROPY (the mathematical concept not the network).
> If the current systme of a fixed 3 hops was changed to allow 3-6 hops then
> I think this would create a much LESS predictable system.
> Pulling the records on a ALL our TOR servers is possible. And then going
> through them records to see the 3 fixed hops by computer is simple!
> You then only need to monitor the traget web site to see the EXIT server
> and follow them back. Remeber all US, European, Australasian & many Asian
> govs are now co-operating. so much of the data is ALREADY being pooled.
> BUT if a random 3 to 6 hops was the norm then TOR becomes much less
> predictable and the computers now have to do mulptile path analysis for 3
> to6 nodes, instead of just 3.
> Ok so not everyone would need this, or want it and ewe dont know the
> effects on the system.
> It looks like we have enough middle men to cope so why not give it a go.
> Allow the users to set their min and max hops (3 to 6) and let TOR client
> portion set up random length circuits within those limits.
> If this was to be tried out it would be best to use 3 to 4 in the intial
> version and see how it goes.
> Also to hinder timiing attacks and log lookup software it would be a good
> idea to allow the TOR client side to specify random "delay" for the hops to
> put into its packets. Specify max packet delay time and then the hop
> randomly distributes between this and zero delay, some packets might then
> get forwarded in the wrong order, that would further confuse any attack
> software. I say this should be the clients instruction because they may not
> want any delay (eg for streams such as voip).
> Once again a little at a time, from one version to the next!
> Ok .. i'm done.
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