Certainly. Take a look at the handbook section: https://www.freebsd.org/doc/handbook/swap-encrypting.html
It assumes a UFS file system where /dev/ada0s1b is the swap partition.
It assumes an MBR partitioned disk ada0 where /dev/ada0s1b is the swap partition.
Fixed in r47811, thanks!I noticed a small error in that section:
I usually just do it from the install menu when I setup my server using ZFS as the file system. They offer a great book "The Design And Implementation Of The FreeBSD Operating System." Long title but a great read and reference for stuff like this. It will take you from n00b to systems admin in no time. Linux was driving me insane so I spent 3 months learning BSD and haven't looked back since.