How do I generate random bytes with
Another command in
rand. We invoke it like this:
$ openssl rand -hex 10 aa27660aa7e186902981
10 indicates the number of random bytes to print to standard out.
-hex prints those bytes in hex format - 2 characters per byte, so 20 characters.
The output comes from a PRNG. The PRNG is seeded with, amongst other randomness sources, a file at
~/.rnd. This file contains random bytes:
$ cat ~/.rnd 33k�ɱ��%�*��#Yn�� ]w$Lkn���M|cW@9%V ...
OpenSSL apparently uses this location to store previously-gathered entropy. You can delete it at any time without any ill effects.
I wrote this because I said I'd learn OpenSSL; `rand` is another tool in the toolbox This post is not associated with my employer. This site is hosted by Netlify (who are great, but I'm not associated with them either).