@node disk_images
@section Disk Images
-Since version 0.6.1, QEMU supports many disk image formats, including
-growable disk images (their size increase as non empty sectors are
-written), compressed and encrypted disk images. Version 0.8.3 added
-the new qcow2 disk image format which is essential to support VM
-snapshots.
+QEMU supports many disk image formats, including growable disk images
+(their size increase as non empty sectors are written), compressed and
+encrypted disk images.
@menu
* disk_images_quickstart:: Quick start for disk image creation
@item backing_fmt
Image format of the base image
@item encryption
-If this option is set to @code{on}, the image is encrypted with 128-bit AES-CBC.
+This option is deprecated and equivalent to @code{encrypt.format=aes}
+
+@item encrypt.format
-The use of encryption in qcow and qcow2 images is considered to be flawed by
-modern cryptography standards, suffering from a number of design problems:
+If this is set to @code{luks}, it requests that the qcow2 payload (not
+qcow2 header) be encrypted using the LUKS format. The passphrase to
+use to unlock the LUKS key slot is given by the @code{encrypt.key-secret}
+parameter. LUKS encryption parameters can be tuned with the other
+@code{encrypt.*} parameters.
+
+If this is set to @code{aes}, the image is encrypted with 128-bit AES-CBC.
+The encryption key is given by the @code{encrypt.key-secret} parameter.
+This encryption format is considered to be flawed by modern cryptography
+standards, suffering from a number of design problems:
@itemize @minus
@item The AES-CBC cipher is used with predictable initialization vectors based
though even this is ineffective with many modern storage technologies.
@end itemize
-Use of qcow / qcow2 encryption with QEMU is deprecated, and support for
-it will go away in a future release. Users are recommended to use an
-alternative encryption technology such as the Linux dm-crypt / LUKS
-system.
+The use of this is no longer supported in system emulators. Support only
+remains in the command line utilities, for the purposes of data liberation
+and interoperability with old versions of QEMU. The @code{luks} format
+should be used instead.
+
+@item encrypt.key-secret
+
+Provides the ID of a @code{secret} object that contains the passphrase
+(@code{encrypt.format=luks}) or encryption key (@code{encrypt.format=aes}).
+
+@item encrypt.cipher-alg
+
+Name of the cipher algorithm and key length. Currently defaults
+to @code{aes-256}. Only used when @code{encrypt.format=luks}.
+
+@item encrypt.cipher-mode
+
+Name of the encryption mode to use. Currently defaults to @code{xts}.
+Only used when @code{encrypt.format=luks}.
+
+@item encrypt.ivgen-alg
+
+Name of the initialization vector generator algorithm. Currently defaults
+to @code{plain64}. Only used when @code{encrypt.format=luks}.
+
+@item encrypt.ivgen-hash-alg
+
+Name of the hash algorithm to use with the initialization vector generator
+(if required). Defaults to @code{sha256}. Only used when @code{encrypt.format=luks}.
+
+@item encrypt.hash-alg
+
+Name of the hash algorithm to use for PBKDF algorithm
+Defaults to @code{sha256}. Only used when @code{encrypt.format=luks}.
+
+@item encrypt.iter-time
+
+Amount of time, in milliseconds, to use for PBKDF algorithm per key slot.
+Defaults to @code{2000}. Only used when @code{encrypt.format=luks}.
@item cluster_size
Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster
@item backing_file
File name of a base image (see @option{create} subcommand)
@item encryption
-If this option is set to @code{on}, the image is encrypted.
+This option is deprecated and equivalent to @code{encrypt.format=aes}
+
+@item encrypt.format
+If this is set to @code{aes}, the image is encrypted with 128-bit AES-CBC.
+The encryption key is given by the @code{encrypt.key-secret} parameter.
+This encryption format is considered to be flawed by modern cryptography
+standards, suffering from a number of design problems enumerated previously
+against the @code{qcow2} image format.
+
+The use of this is no longer supported in system emulators. Support only
+remains in the command line utilities, for the purposes of data liberation
+and interoperability with old versions of QEMU.
+
+Users requiring native encryption should use the @code{qcow2} format
+instead with @code{encrypt.format=luks}.
+
+@item encrypt.key-secret
+
+Provides the ID of a @code{secret} object that contains the encryption
+key (@code{encrypt.format=aes}).
+
+@end table
+
+@item luks
+
+LUKS v1 encryption format, compatible with Linux dm-crypt/cryptsetup
+
+Supported options:
+@table @code
+
+@item key-secret
+
+Provides the ID of a @code{secret} object that contains the passphrase.
+
+@item cipher-alg
+
+Name of the cipher algorithm and key length. Currently defaults
+to @code{aes-256}.
+
+@item cipher-mode
+
+Name of the encryption mode to use. Currently defaults to @code{xts}.
+
+@item ivgen-alg
+
+Name of the initialization vector generator algorithm. Currently defaults
+to @code{plain64}.
+
+@item ivgen-hash-alg
+
+Name of the hash algorithm to use with the initialization vector generator
+(if required). Defaults to @code{sha256}.
+
+@item hash-alg
+
+Name of the hash algorithm to use for PBKDF algorithm
+Defaults to @code{sha256}.
+
+@item iter-time
+
+Amount of time, in milliseconds, to use for PBKDF algorithm per key slot.
+Defaults to @code{2000}.
+
@end table
@item vdi
@end table
+@c man end
+
@node ColdFire System emulator
@section ColdFire System emulator
@cindex system emulation (ColdFire)
@end table
+@c man end
+
@node Cris System emulator
@section Cris System emulator
@cindex system emulation (Cris)
@end table
+@c man end
+
@node QEMU Guest Agent
@chapter QEMU Guest Agent invocation
projects / mirror_qemu.git / blobdiff