NAME

     zfs-load-key — load, unload, or change encryption key of ZFS dataset

SYNOPSIS

     zfs load-key [-nr] [-L keylocation] -a|filesystem
     zfs unload-key [-r] -a|filesystem
     zfs change-key [-l] [-o keylocation=value] [-o keyformat=value] [-o pbkdf2iters=value] filesystem
     zfs change-key -i [-l] filesystem

DESCRIPTION

     zfs load-key [-nr] [-L keylocation] -a|filesystem
       Load the key for filesystem, allowing it and all children that inherit the keylocation property to be
       accessed.  The key will be expected in the format specified by the keyformat and location specified by
       the keylocation property.  Note that if the keylocation is set to prompt the terminal will interactively
       wait for the key to be entered.  Loading a key will not automatically mount the dataset.  If that
       functionality is desired, zfs mount -l will ask for the key and mount the dataset (see zfs-mount(8)).
       Once the key is loaded the keystatus property will become available.

       -r  Recursively loads the keys for the specified filesystem and all descendent encryption roots.

       -a  Loads the keys for all encryption roots in all imported pools.

       -n  Do a dry-run ("No-op") load-key.  This will cause zfs to simply check that the provided key is
           correct.  This command may be run even if the key is already loaded.

       -L keylocation
           Use keylocation instead of the keylocation property.  This will not change the value of the property
           on the dataset.  Note that if used with either -r or -a, keylocation may only be given as prompt.

     zfs unload-key [-r] -a|filesystem
       Unloads a key from ZFS, removing the ability to access the dataset and all of its children that inherit
       the keylocation property.  This requires that the dataset is not currently open or mounted.  Once the key
       is unloaded the keystatus property will become unavailable.

       -r  Recursively unloads the keys for the specified filesystem and all descendent encryption roots.

       -a  Unloads the keys for all encryption roots in all imported pools.

     zfs change-key [-l] [-o keylocation=value] [-o keyformat=value] [-o pbkdf2iters=value] filesystem

     zfs change-key -i [-l] filesystem
       Changes the user's key (e.g. a passphrase) used to access a dataset.  This command requires that the
       existing key for the dataset is already loaded.  This command may also be used to change the keylocation,
       keyformat, and pbkdf2iters properties as needed.  If the dataset was not previously an encryption root it
       will become one.  Alternatively, the -i flag may be provided to cause an encryption root to inherit the
       parent's key instead.

       If the user's key is compromised, zfs change-key does not necessarily protect existing or newly-written
       data from attack.  Newly-written data will continue to be encrypted with the same master key as the
       existing data.  The master key is compromised if an attacker obtains a user key and the corresponding
       wrapped master key.  Currently, zfs change-key does not overwrite the previous wrapped master key on
       disk, so it is accessible via forensic analysis for an indeterminate length of time.

       In the event of a master key compromise, ideally the drives should be securely erased to remove all the
       old data (which is readable using the compromised master key), a new pool created, and the data copied
       back.  This can be approximated in place by creating new datasets, copying the data (e.g. using zfs send
       | zfs recv), and then clearing the free space with zpool trim --secure if supported by your hardware,
       otherwise zpool initialize.

       -l  Ensures the key is loaded before attempting to change the key.  This is effectively equivalent to
           running zfs load-key filesystem; zfs change-key filesystem

       -o property=value
           Allows the user to set encryption key properties (keyformat, keylocation, and pbkdf2iters) while
           changing the key.  This is the only way to alter keyformat and pbkdf2iters after the dataset has been
           created.

       -i  Indicates that zfs should make filesystem inherit the key of its parent.  Note that this command can
           only be run on an encryption root that has an encrypted parent.

   Encryption
     Enabling the encryption feature allows for the creation of encrypted filesystems and volumes.  ZFS will
     encrypt file and volume data, file attributes, ACLs, permission bits, directory listings, FUID mappings,
     and userused/groupused data.  ZFS will not encrypt metadata related to the pool structure, including
     dataset and snapshot names, dataset hierarchy, properties, file size, file holes, and deduplication tables
     (though the deduplicated data itself is encrypted).

     Key rotation is managed by ZFS.  Changing the user's key (e.g. a passphrase) does not require re-encrypting
     the entire dataset.  Datasets can be scrubbed, resilvered, renamed, and deleted without the encryption keys
     being loaded (see the load-key subcommand for more info on key loading).

     Creating an encrypted dataset requires specifying the encryption and keyformat properties at creation time,
     along with an optional keylocation and pbkdf2iters.  After entering an encryption key, the created dataset
     will become an encryption root.  Any descendant datasets will inherit their encryption key from the
     encryption root by default, meaning that loading, unloading, or changing the key for the encryption root
     will implicitly do the same for all inheriting datasets.  If this inheritance is not desired, simply supply
     a keyformat when creating the child dataset or use zfs change-key to break an existing relationship,
     creating a new encryption root on the child.  Note that the child's keyformat may match that of the parent
     while still creating a new encryption root, and that changing the encryption property alone does not create
     a new encryption root; this would simply use a different cipher suite with the same key as its encryption
     root.  The one exception is that clones will always use their origin's encryption key.  As a result of this
     exception, some encryption-related properties (namely keystatus, keyformat, keylocation, and pbkdf2iters)
     do not inherit like other ZFS properties and instead use the value determined by their encryption root.
     Encryption root inheritance can be tracked via the read-only encryptionroot property.

     Encryption changes the behavior of a few ZFS operations.  Encryption is applied after compression so
     compression ratios are preserved.  Normally checksums in ZFS are 256 bits long, but for encrypted data the
     checksum is 128 bits of the user-chosen checksum and 128 bits of MAC from the encryption suite, which
     provides additional protection against maliciously altered data.  Deduplication is still possible with
     encryption enabled but for security, datasets will only deduplicate against themselves, their snapshots,
     and their clones.

     There are a few limitations on encrypted datasets.  Encrypted data cannot be embedded via the embedded_data
     feature.  Encrypted datasets may not have copies=3 since the implementation stores some encryption metadata
     where the third copy would normally be.  Since compression is applied before encryption, datasets may be
     vulnerable to a CRIME-like attack if applications accessing the data allow for it.  Deduplication with
     encryption will leak information about which blocks are equivalent in a dataset and will incur an extra CPU
     cost for each block written.

SEE ALSO

     zfsprops(7), zfs-create(8), zfs-set(8)