Where's the trust?
Unless they open-source the firmware and it's analyzed by cryptologists, it can't be trusted.
No encryption with closed source should be trusted. If it were actually good encryption, they'd be happy to have everyone look at the source and bolster their image as secure. If they keep it secret, the obvious assumption is that it's not very good and they want to keep that a secret.
Better to use Truecrypt - Open source and not cracked yet.