NAME¶

volume_key - work with volume encryption secrets and escrow packets

SYNOPIS¶

volume_key [OPTION]... OPERAND...

DESCRIPTION¶

volume_key extracts "secrets" used for volume encryption (for example keys or passphrases) and stores them into separate encrypted "escrow packets", uses a previously created escrow packet to restore access to a volume (e.g. if the user forgets a passphrase), or manipulates the information in escrow packets.

The mode of operation and operands of volume_key are determined by specifying one of the --save, --restore, --setup-volume, --reencrypt, --dump or --secrets options. See the OPTIONS sections for details.

OPTIONS¶

In all options described below, VOLUME is a LUKS device, not the plaintext device containted within:

The following options determine the mode of operation and expected operands of volume_key:

--save

Expects operands VOLUME [PACKET]. Open VOLUME. If PACKET is provided, load the secrets from it. Otherwise, extract secrets from VOLUME, prompting the user if necessary. In any case, store secrets in one or more output packets.

--restore

Expects operands VOLUME PACKET. Open VOLUME and use the secrets in PACKET to make VOLUME accessible again, prompting the user if necessary (e.g. by letting the user enter a new passphrase).

--setup-volume

Expects operands VOLUME PACKET NAME. Open VOLUME and use the secrets in PACKET to set up VOLUME for use of the decrypted data as NAME.

Currently NAME is a name of a dm-crypt volume, and this operation makes the decrypted volume available as /dev/mapper/NAME.

This operation should not permanently alter VOLUME (e.g. by adding a new passphrase); the user can of course access and modify the decrypted volume, modifying VOLUME in the process.

--reencrypt

Expects operand PACKET. Open PACKET, decrypting it if necessary, and store the information in one or more new output packets.

--dump

Expects operand PACKET. Open PACKET, decrypting it if necessary, and output the contents of PACKET. The secrets are not output by default.

--secrets

Expects operand PACKET. Open PACKET, decrypting it if necessary, and output secrets contained in PACKET.

--help

Show usage information.

--version

Show version of volume_key.

The following options alter the behavior of the specified operation:

-b, --batch

Run in batch mode. Read passwords and passphrases from standard input, each terminated by a NUL character. If a packet does not match a volume exactly, fail instead of prompting the user.

-d, --nss-dir DIR

Use private keys in NSS database in DIR to decrypt public key-encrypted packets.

-o, --output PACKET

Write the default secret to PACKET.

Which secret is the default depends on volume format: it should not be likely to expire, and it should allow restoring access to the volume using --restore.

--output-data-encryption-key PACKET

Write the data encryption key (the key directly used to encrypt the actual volume data) to PACKET.

--output-passphrase PACKET

Write a passphrase that can be used to access the volume to PACKET.

--create-random-passphrase PACKET

Generate a random alphanumeric passphrase, add it to VOLUME (without affecting other passphrases) and store the random passphrase into PACKET.

-c, --certificate CERT

Load a certificate from the file specified by CERT and encrypt all output packets using the public key contained in the certificate. If this option is not specified, all output packets are encrypted using a passphrase.

Note that CERT is a certificate file name, not a NSS certificate nickname.

--output-format FORMAT

Use FORMAT for all output packets. FORMAT can currently be one of asymmetric (use CMS to encrypt the whole packet, requires a certificate), asymmetric_wrap_secret_only (wrap only the secret, requires a certificate), passphrase (use GPG to encrypt the whole packet, requires a passphrase).

--with-secrets

Include secrets in the output of --dump

EXIT STATUS¶

volume_key returns with exit status 0 on success, 1 on error.

NOTES¶

The only currently supported volume format is LUKS.

EXAMPLE¶

Typical usage of volume_key proceeds as follows. During system installation or soon after, back up the default secret of a volume, and add a system-specific random passphrase. Encrypt both using a certificate:

If the user forgets a passphrase, and the you can access the computer, decrypt PACKET_DEFAULT using the certificate private key (which should never leave a secure machine):

If the user forgets the passphrase, and you cannot access the computer, decrypt the backup passphrase: