[147112] in cryptography@c2.net mail archive
[Cryptography] Credit for Trusting Trust
daemon@ATHENA.MIT.EDU (Jerry Leichter)
Sat Sep 14 10:30:44 2013
X-Original-To: cryptography@metzdowd.com
From: Jerry Leichter <leichter@lrw.com>
In-Reply-To: <20130912195327.GD3175@gmail.com>
Date: Fri, 13 Sep 2013 23:22:11 -0400
To: Nico Williams <nico@cryptonector.com>
Cc: "cryptography@metzdowd.com List" <cryptography@metzdowd.com>
Errors-To: cryptography-bounces+crypto.discuss=bloom-picayune.mit.edu@metzdowd.com
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> ...The goal is to defeat the Thompson attack -- Thompson trojans [the =
classic
> attack described in Ken Thompson's "On Trusting Trust" where the =
compiler inserts code into login and into itself]....
Just to give credit where credit is due: Ken Thompson didn't invent =
this attack, and cites the originators - Paul Karger and Roger Schell, =
way back in 1974, 10 years before Thompson. (Thompson may have produced =
the first working example.) Karger and Schell's work was done for the =
Air Force as part of an analysis of the security of Multics. I never =
met Roger Schell, but I knew Paul at DEC back in the mid 70's. Not =
realizing his connection with the underlying ideas, I showed him =
Thompson's paper. Paul explained how to counter it by examining the =
compiler output (not practical except in specialized circumstances) but =
never brought up his own role.
Sadly, he died too young in 2010. He deserves to be credited.
The full details can be found on David A. Wheeler's page at =
http://www.dwheeler.com/trusting-trust/. (Wheeler's 2005 dissertation =
provides a complete solution to the problem; he cites Henry Spencer for =
suggesting the idea underlying his formal treatment back in 1998.)
-- Jerry
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<html><head></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; =
"><div><blockquote type=3D"cite"><div><font class=3D"Apple-style-span" =
color=3D"#000000">...</font>The goal is to defeat the Thompson attack -- =
Thompson trojans [the classic<br></div></blockquote><blockquote =
type=3D"cite"><div>attack described in Ken Thompson's "On Trusting =
Trust" where the compiler inserts code into login and into =
itself]....<br></div></blockquote>Just to give credit where credit is =
due: Ken Thompson didn't invent this attack, and cites the =
originators - Paul Karger and Roger Schell, way back in 1974, 10 years =
before Thompson. (Thompson may have produced the first working =
example.) Karger and Schell's work was done for the Air Force as =
part of an analysis of the security of Multics. I never met Roger =
Schell, but I knew Paul at DEC back in the mid 70's. Not realizing =
his connection with the underlying ideas, I showed him Thompson's paper. =
Paul explained how to counter it by examining the compiler output =
(not practical except in specialized circumstances) but never brought up =
his own role.</div><div><br></div><div>Sadly, he died too young in 2010. =
He deserves to be credited.</div><div><br></div><div>The full =
details can be found on David A. Wheeler's page at <a =
href=3D"http://www.dwheeler.com/trusting-trust/">http://www.dwheeler.com/t=
rusting-trust/</a>. (Wheeler's 2005 dissertation provides a =
complete solution to the problem; he cites Henry Spencer for suggesting =
the idea underlying his formal treatment back in =
1998.)</div><div><br></div><div><div> =
=
=
-- =
Jerry</div><div><br></div></div><br></body></html>=
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