There's enough in their service description to not trust them.
The way the system is described, you encrypt a file on your device, upload both the key and the file to the cloud, then the receiver downloads both the file and the key.
The "encryption key storage" is central to how the whole thing works. It's also a dumb idea. The only thing I can think is that it allows a file to be delivered out-of-band, but the inescapable fact is that decryption material is available to at least one other party.
The way the system is described, you encrypt a file on your device, upload both the key and the file to the cloud, then the receiver downloads both the file and the key.
Look at the diagrams here: https://www.virtru.com/how-virtru-works
The "encryption key storage" is central to how the whole thing works. It's also a dumb idea. The only thing I can think is that it allows a file to be delivered out-of-band, but the inescapable fact is that decryption material is available to at least one other party.