man
8 cryptsetup-benchmark
CRYPTSETUP-BENCHMARK(8) Maintenance Commands CRYPTSETUP-BENCHMARK(8)
NAME
cryptsetup-benchmark - benchmarks ciphers and KDF
SYNOPSIS
cryptsetup benchmark [<options>]
DESCRIPTION
Benchmarks ciphers and KDF (key derivation function). Without
parameters, it tries to measure few common configurations.
To benchmark other ciphers or modes, you need to specify --cipher and
--key-size options.
To benchmark PBKDF you need to specify --pbkdf or --hash with optional
cost parameters --iter-time, --pbkdf-memory or --pbkdf-parallel.
NOTE: This benchmark uses memory only and is only informative. You
cannot directly predict real storage encryption speed from it.
For testing block ciphers, this benchmark requires kernel userspace
crypto API to be available (introduced in Linux kernel 2.6.38). If you
are configuring kernel yourself, enable "User-space interface for
symmetric key cipher algorithms" in "Cryptographic API" section
(CRYPTO_USER_API_SKCIPHER .config option).
<options> can be [--cipher, --key-size, --hash, --pbkdf, --iter-time,
--pbkdf-memory, --pbkdf-parallel].
OPTIONS
--batch-mode, -q
Suppresses all confirmation questions. Use with care!
If the --verify-passphrase option is not specified, this option
also switches off the passphrase verification.
--cipher, -c <cipher-spec>
Set the cipher specification string.
--debug or --debug-json
Run in debug mode with full diagnostic logs. Debug output lines are
always prefixed by #.
If --debug-json is used, additional LUKS2 JSON data structures are
printed.
--hash, -h <hash-spec>
The specified hash is used for PBKDF2 and AF splitter.
--help, -?
Show help text and default parameters.
--iter-time, -i <number of milliseconds>
The number of milliseconds to spend with PBKDF passphrase
processing. Specifying 0 as parameter selects the compiled-in
default.
--key-size, -s bits
Sets key size in bits. The argument has to be a multiple of 8. The
possible key-sizes are limited by the cipher and mode used.
See /proc/crypto for more information. Note that key-size in
/proc/crypto is stated in bytes.
This option can be used for open --type plain or luksFormat. All
other LUKS actions will use the key-size specified in the LUKS
header. Use cryptsetup --help to show the compiled-in defaults.
--pbkdf <PBKDF spec>
Set Password-Based Key Derivation Function (PBKDF) algorithm for
LUKS keyslot. The PBKDF can be: pbkdf2 (for PBKDF2 according to
RFC2898), argon2i for Argon2i or argon2id for Argon2id (see Argon2
<https://www.cryptolux.org/index.php/Argon2> for more info).
For LUKS1, only PBKDF2 is accepted (no need to use this option).
The default PBKDF for LUKS2 is set during compilation time and is
available in cryptsetup --help output.
A PBKDF is used for increasing dictionary and brute-force attack
cost for keyslot passwords. The parameters can be time, memory and
parallel cost.
For PBKDF2, only time cost (number of iterations) applies. For
Argon2i/id, there is also memory cost (memory required during the
process of key derivation) and parallel cost (number of threads
that run in parallel during the key derivation.
Note that increasing memory cost also increases time, so the final
parameter values are measured by a benchmark. The benchmark tries
to find iteration time (--iter-time) with required memory cost
--pbkdf-memory. If it is not possible, the memory cost is decreased
as well. The parallel cost --pbkdf-parallel is constant and is
checked against available CPU cores.
You can see all PBKDF parameters for particular LUKS2 keyslot with
cryptsetup-luksDump(8) command.
NOTE: If you do not want to use benchmark and want to specify all
parameters directly, use --pbkdf-force-iterations with
--pbkdf-memory and --pbkdf-parallel. This will override the values
without benchmarking. Note it can cause extremely long unlocking
time or cause out-of-memory conditions with unconditional process
termination. Use only in specific cases, for example, if you know
that the formatted device will be used on some small embedded
system.
MINIMAL AND MAXIMAL PBKDF COSTS: For PBKDF2, the minimum iteration
count is 1000 and maximum is 4294967295 (maximum for 32bit unsigned
integer). Memory and parallel costs are unused for PBKDF2. For
Argon2i and Argon2id, minimum iteration count (CPU cost) is 4 and
maximum is 4294967295 (maximum for 32bit unsigned integer). Minimum
memory cost is 32 KiB and maximum is 4 GiB. (Limited by addressable
memory on some CPU platforms.) If the memory cost parameter is
benchmarked (not specified by a parameter) it is always in range
from 64 MiB to 1 GiB. The parallel cost minimum is 1 and maximum 4
(if enough CPUs cores are available, otherwise it is decreased).
--pbkdf-memory <number>
Set the memory cost for PBKDF (for Argon2i/id the number represents
kilobytes). Note that it is maximal value, PBKDF benchmark or
available physical memory can decrease it. This option is not
available for PBKDF2.
--pbkdf-parallel <number>
Set the parallel cost for PBKDF (number of threads, up to 4). Note
that it is maximal value, it is decreased automatically if CPU
online count is lower. This option is not available for PBKDF2.
--usage
Show short option help.
--version, -V
Show the program version.
REPORTING BUGS
Report bugs at cryptsetup mailing list <cryptsetup@lists.linux.dev> or
in Issues project section
<https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.
Please attach output of the failed command with --debug option added.
SEE ALSO
Cryptsetup FAQ
<https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>
cryptsetup(8), integritysetup(8) and veritysetup(8)
CRYPTSETUP
Part of cryptsetup project <https://gitlab.com/cryptsetup/cryptsetup/>.
cryptsetup 2.7.2 2025-06-13 CRYPTSETUP-BENCHMARK(8)