# Create a mirrored pool:
zpool create tank mirror /dev/sdb /dev/sdc

# On a zpool that supports encryption, encryption may be enabled as follows:
zpool set feature@encryption=enabled [pool] 

# Create an encrypted dataset:
zfs create -o encryption=on -o keylocation=prompt -o keyformat=passphrase [dataset]
# where [dataset] may be a child of an existing non-encrypted dataset, e.g. tank/enc1;
# This will prompt for the encryption passphrase for this zfs dataset.

# An encrypted zfs dataset may be mounted as follows:
zfs mount -l [/pool/]dataset]
# This will prompt for the encryption passphrase for this zfs dataset
# and mount the encrypted dataset.