We currently sign our factory images releases with the signify tool from OpenBSD. It provides tiny signatures that are easy to verify on any distribution with signify in their repositories. This is much less important than in the past because you can verify the completed install.
In 2012, shortly after #SLS was announced, #NASA officials estimated that each mission would cost about $500 million — with the rocket targeting a 2017 debut. Today, the #cost has ballooned eightfold 💰, according to the NASA #auditor.