KCAPI-RNG(1) General Commands Manual KCAPI-RNG(1)

# [NAME](#NAME)

kcapi-rng - Kernel Crypto API Random Number Gatherer

# [SYNOPSIS](#SYNOPSIS)

**kcapi-rng** \[*OPTION*]

# [DESCRIPTION](#DESCRIPTION)

The *kcapi-rng* application provides tool to obtain random numbers from the Linux kernel crypto API via the command line. The tool is similar to reading */dev/hwrand* with the difference that the used random number generators are fully deterministic - i.e. they are DRNGs.

Any potential seed data can be provided via STDIN. Some of the DRNGs require seeding as they do not seed themselves. The *kcapi-rng* tool ensures that the DRNGs are seeded by pulling the seed data from the *getrandom* system call (or */dev/urandom* if *getrandom* is not available). The amount of seed data is defined by the DRNG itself and can be reviewed by assessing */proc/crypto*. The seed provided via STDIN will be added to the internally-generated seed. The generated random numbers are written to STDOUT.

The following options are supported when invoking *kcapi-rng*:

[**-b**, **--bytes BYTES**](#b)

Generate *BYTES* number of random bytes.

[**-n**, **--name NAME**](#n)

The *NAME* argument specifies the random number generator implementation to be used. The allowed random number generators are defined by the Linux kernel. Currently registered ciphers can be reviewed at */proc/crypto*. The content of this file, however, can change when new ciphers are registered. The *NAME* argument is given directly to the Linux kernel crypto API. The chosen cipher must be of type *rng* as marked in */proc/crypto*. If this option is not used, the cipher *stdrng* is used as default.

[**--hex**](#hex)

The generated random numbers are print out in hexadecimal notation instead of as binary string.

[**-v**, **--verbose**](#v)

Enable a verbose operation of *kcapi-rng*. Using this option multiple times increases the verbosity.

[**-q**, **--quiet**](#q)

Prevent the generation of any log output.

[**-h**, **--help**](#h)

Display the help text.

[**--version**](#version)

Display the version number of the *kcapi-rng* application.

# [SEE ALSO](#SEE_ALSO)

[**kcapi-enc**(1)](/man/os/libkcapi/kcapi-enc.1) [**kcapi-dgst**(1)](/man/os/libkcapi/kcapi-dgst.1) [**kcapi-hasher**(1)](/man/os/libkcapi/kcapi-hasher.1)

2017-08-14

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Document: kcapi-rng(1) from libkcapi 1.5.1-r1 (Chainguard OS)
Source: https://github.com/smuellerDD/libkcapi