A colleague implemented something like this by creating a function that could be called from various places at random times, such as the ethernet driver (ether_input()), serial port modem signal changes, etc. The function would read the HAL microsecond clock value and write the lower 16-bits to /dev/random. After a pre-determined number of such events, this function would stop writing to /dev/random and simply return.
Jay -----Original Message----- From: Grant Edwards [mailto:[EMAIL PROTECTED] Sent: Thursday, April 03, 2008 12:18 PM To: [EMAIL PROTECTED] Subject: [ECOS] Re: Entropy gathering? On 2008-04-03, Grant Edwards <[EMAIL PROTECTED]> wrote: > The BSD stacks appear to use an aRC4 keystream for "random" > data. The stream uses a constant seed and then mixes in the > system clock value. It could be worse, but it's not great > either. Upon reading the above statement, I think I should clarify that the "system time" that's mixed in is the HAL's hardware counter value and not the system tick count time. The hardware counter is changing much faster (a good thing), but it provides relatively few bits (on my targets, it ranges from 14-18). -- Grant Edwards grante Yow! My mind is making at ashtrays in Dayton ... visi.com -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
