Re: Challenge to TCPA/Palladium detractors
Anon wrote:
You could even have each participant compile the program himself, but still each app can recognize the others on the network and cooperate with them.
Matt Crawford replied:
Unless the application author can predict the exact output of the compilers, he can't issue a signature on the object code. The compilers then have to be inside the trusted base, checking a signature on the source code and reflecting it somehow through a signature they create for the object code.
It's likely that only a limited number of compiler configurations would be in common use, and signatures on the executables produced by each of those could be provided. Then all the app writer has to do is to tell people, get compiler version so-and-so and compile with that, and your object will match the hash my app looks for. DEI --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@wasabisystems.com
Anonymous wrote:
Matt Crawford replied:
Unless the application author can predict the exact output of the compilers, he can't issue a signature on the object code. The compilers then have to be inside the trusted base, checking a signature on the source code and reflecting it somehow through a signature they create for the object code.
It's likely that only a limited number of compiler configurations would be in common use, and signatures on the executables produced by each of those could be provided. Then all the app writer has to do is to tell people, get compiler version so-and-so and compile with that, and your object will match the hash my app looks for. DEI
The above view may be overly optimistic. IIRC, nobody outside PGP was ever able to compile a PGP binary from source that matched the hash of the binaries built by PGP. --Lucky Green --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@wasabisystems.com
I'm not surprised that most people couldn't produce a matching PGP executbales - most compilers (irrespective of compiler optimisation options etc) include a timestamp in the executable. Regards, Sam Simpson sam@samsimpson.com http://www.samsimpson.com/ Mob: +44 (0) 7866 726060 Home Office: +44 (0) 1438 229390 Fax: +44 (0) 1438 726069 On Fri, 9 Aug 2002, Lucky Green wrote:
Anonymous wrote:
Matt Crawford replied:
Unless the application author can predict the exact output of the compilers, he can't issue a signature on the object code. The compilers then have to be inside the trusted base, checking a signature on the source code and reflecting it somehow through a signature they create for the object code.
It's likely that only a limited number of compiler configurations would be in common use, and signatures on the executables produced by each of those could be provided. Then all the app writer has to do is to tell people, get compiler version so-and-so and compile with that, and your object will match the hash my app looks for. DEI
The above view may be overly optimistic. IIRC, nobody outside PGP was ever able to compile a PGP binary from source that matched the hash of the binaries built by PGP.
--Lucky Green
--------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@wasabisystems.com
participants (3)
-
AARG!Anonymous -
Lucky Green -
Sam Simpson