Can NetBSD cgd be used for encrypted backup?

[Mayuresh <mayuresh%acm.org@localhost>]

I am coming from encfs/cryfs on Linux, which allow encryption at directory
level. A user space mount shows the unencrypted contents, while the
physical disk has encrypted contents, which can be easily backed up.

encfs on NetBSD seems broken and dated to me, while cryfs doesn't seem to
be available (contrary to wikipedia page
https://en.wikipedia.org/wiki/Comparison_of_disk_encryption_software#Operating_systems
)

Have a few questions about cgd in this context:

- Can the native cgd of NetBSD be used for the purpose of encrypted
  backup? Basically can I mount such filesystem in a way that it shows
  encrypted files?

- Can I use a virtual filesystem (loop device/vnode disk) with cgd?

- Can I dynamically grow such virtual filesystem as the space requirement
  grows?

Mayuresh