Question - seeding the hw pseudo random number generator

Stephan Müller smueller at
Sat Mar 25 21:10:44 PDT 2017

Am Donnerstag, 23. März 2017, 10:44:06 CEST schrieb Herbert Xu:

Hi Herbert,

> On Thu, Mar 23, 2017 at 09:23:07AM +0100, Corentin Labbe wrote:
> > Problem with this conversion, a huge regression for user space.
> > Using hwrng is simple as cat /dev/hwrng.
> > Using algif_rng via AF_ALG is ... unusable for the moment.
> > Perhaps creating an user space tool (prng-tool which provide a cat
> > /dev/hwrng replacement) is mandatory before any convertion.
> Stephan may have a tool to do this.  Stephan?

I added the application kcapi-rng to HEAD of [1]. Create the application with 
the --enable-kcapi-rngapp configure option.

$ kcapi-rng 

Kernel Crypto API Random Number Gatherer

Kernel Crypto API interface library version: libkcapi pre-release 0.13.1
Reported numeric version number 130080

        -b --bytes <BYTES>      Number of bytes to generate (required option)
        -h --help       This help information
           --version    Print version
        -v --verbose    Verbose logging, multiple options increase verbosity

Data provided at stdin is used to seed the DRNG



More information about the linux-arm-kernel mailing list