APT security and buildds
For etch, we will have apt security in place, so we can be sure that the stuff comes from the correct archive. But it is not possible to disable that checks only for one source, just for anything.
Buildds uses at least one mirror: incoming.debian.org aka ftp-master.debian.org. There are two queues, the accepted autobuild queue and the main archive. The accepted autobuild queue is not signed at all, it does not provide a Release file. The archive needs some time to generate the Packages files each dinstall run and have broken sigs during this time.
This means: buildds can't use APT security at all. And no, there is no other mechanism to ensure data integrity.
