[118743] in Cypherpunks
RE: Unplugged! The biggest hack in history
daemon@ATHENA.MIT.EDU (Lucky Green)
Thu Oct 7 03:21:04 1999
Date: Thu, 07 Oct 1999 00:07:54 -0700
From: Lucky Green <shamrock@cypherpunks.to>
In-reply-to: <199910070600.CAA09136@mail1.radix.net>
To: "John A. Limpert" <johnl@radix.net>,
Sean Roach <roach_s@mail.intplsrv.net>, cypherpunks@Algebra.COM
Message-id: <NDBBIFGOKODBCKDGJDKLAECACJAA.shamrock@cypherpunks.to>
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Reply-To: Lucky Green <shamrock@cypherpunks.to>
I am just catching the tail end of this thread, but why in the world would
somebody in LE pay for a custom-built device to perform blind demod when you
can buy off-the-shelf devices that perform blind demod on V.90 connections
from Applied Signal?
--Lucky Green <shamrock@cypherpunks.to>
> -----Original Message-----
> From: owner-cypherpunks@Algebra.COM
> [mailto:owner-cypherpunks@Algebra.COM]On Behalf Of John A. Limpert
> Sent: Wednesday, October 06, 1999 23:01
> To: Sean Roach; cypherpunks@Algebra.COM
> Subject: Re: Unplugged! The biggest hack in history
>
>
>
> >From: Sean Roach <roach_s@mail.intplsrv.net>
> >
> > Flaws as I see them.
> >
> > I'm assuming, probably erroniously, that a given packet can be
> > checked for errors, up to a certain time, where that time is before
> > the packet has been completely transmitted.
>
> You could compute the probability of having received an error-free packet
> when all but the last N (N < 16) bits have been transmitted. This would
> involve checking the CRC result for the 2**N possible values of the
> remaining N bits. There are probably better ways of doing it than brute
> force.
>
> > Toying with the connection may tip off the bugged that someone is
> > evesdropping.
>
> A simpler method would be to install a bidirectional delay line.
> This would
> allow you to preview the data at the input to the delay line, evaluate it
> and insert hits at the output of the delay line. A TDR (time domain
> reflectometer) would see a unusually long line between the subscriber and
> the central office.
