ssh-rand-helper - Random number gatherer for OpenSSH

ssh-rand-hlper [-vxXh] [-b bytes]

ssh-rand-hlper is a small helper program used by ssh(1), ssh-add(1), ssh-agent(1), ssh-keygen(1), ssh-keyscan(1) and sshd(8) to gather random numbers of cryptographic quality if the openssl(4) library has not been configured to provide them itself.

Normally ssh-rand-hlper will generate a strong random seed and provide it to the calling program via standard output. If standard output is a tty, ssh-rand-hlper will instead print the seed in hexidecimal format unless told otherwise.

ssh-rand-hlper will by default gather random numbers from the system commands listed in /etc/ssh/ssh_prng_cmds. The output of each of the commands listed will be hashed and used to generate a random seed for the calling program. ssh-rand-hlper will also store seed files in ~/.ssh/prng_seed between executions.

Alternately, ssh-rand-hlper may be configured at build time to collect random numbers from a EGD/PRNGd server via a unix domain or localhost tcp socket.

This program is not intended to be run by the end-user, so the few commandline options are for debugging purposes only.

Damien Miller <djm@mindrot.org>

ssh(1), ssh-add(1), ssh-keygen(1), sshd(8)