--- name: "cryptsetup-benchmark" section: "8" platform: "linux" package: "cryptsetup" version: "2.8.8-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/cryptsetup-benchmark" --- # cryptsetup-benchmark(8) benchmarks ciphers and KDF ## NAME cryptsetup-benchmark - benchmarks ciphers and KDF ## SYNOPSIS **cryptsetup** *benchmark* **\[\\]** ## DESCRIPTION *Benchmarks, ciphers and KDF (key derivation function).* *Without parameters, it tries to measure a few common configurations.* *To benchmark other ciphers or modes, 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.* *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 the kernel userspace crypto API to be available.* *If you are configuring the kernel yourself, enable "User-space interface for symmetric key cipher algorithms" in "Cryptographic API" section (CRYPTO\_USER\_API\_SKCIPHER .config option).* **\** *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** *\* *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** *\* *The specified hash is used for PBKDF2 and the AF splitter.* **--help***,* **-?** *Show help text and default parameters.* **--iter-time***,* **-i** *\* *The number of milliseconds to spend with PBKDF passphrase processing.* *Specifying 0 as a 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 the 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** *\* *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 \* *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 the cryptsetup --help output.* *A PBKDF is used for increasing the dictionary and brute-force attack cost for keyslot passwords.* *The parameters can be time, memory and parallel cost.* *For PBKDF2, only the 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 a particular LUKS2 keyslot with the* **cryptsetup-luksDump***(8) command.* *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 the maximum is 4294967295 (maximum for 32-bit unsigned integer).* *Memory and parallel costs are not supported for PBKDF2.* *For* **Argon2i** *and* **Argon2id***, the minimum iteration count (CPU cost) is 4, and the maximum is 4294967295 (maximum for a 32-bit unsigned integer).* *Minimum memory cost is 32 KiB and maximum is 4 GiB.* *If the memory cost parameter is benchmarked (not specified by a parameter), it is always in the range from 64 MiB to 1 GiB.* *Memory cost above 1GiB (up to the 4GiB maximum) can be setup only by the --pbkdf-memory parameter.* *The parallel cost minimum is 1 and maximum 4 (if enough CPU cores are available, otherwise it is decreased by the available CPU cores).* **WARNING:** *Increasing PBKDF computational costs above the mentioned limits provides negligible additional security improvement.* *While elevated costs significantly increase brute-force overhead, they offer negligible protection against dictionary attacks.* *The marginal cost increase for processing an entire dictionary remains fundamentally insufficient.* *The hardcoded PBKDF limits represent engineered trade-offs between cryptographic security and operational usability.* *LUKS maintains portability and must be used within a reasonable time on resource-constrained systems.* *Cryptsetup deliberately restricts maximum memory cost (4 GiB) and parallel cost (4) parameters due to architectural limitations (like embedded and legacy systems).* *PBKDF memory cost mandates actual physical RAM allocation with intensive write operations that must remain in physical RAM.* *Any swap usage results in unacceptable performance degradation.* *Memory management often overcommits allocations beyond available physical memory, expecting most allocated memory to remain unused.* *In such situations, as PBKDF always uses all allocated memory, it frequently causes out-of-memory failures that abort cryptsetup operations.* **--pbkdf-memory** *number* *Set the memory cost for PBKDF (for Argon2i/id, the number represents kilobytes).* *Note that it is the 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 the maximal value; it is decreased automatically if the 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 \* *or in* *Issues project section \.* *Please attach the output of the failed command with --debug option added.* ## SEE ALSO *Cryptsetup FAQ \* **cryptsetup***(8),* **integritysetup***(8) and* **veritysetup***(8)* ## CRYPTSETUP *Part of* *cryptsetup project \.*