Projects / audio-entropyd

audio-entropyd

audio-entropyd feeds the /dev/random device with entropy data read from an audio device. The audio data is not copied as is, but first 'de-biased' and analyzed to determine how many bits of entropy are in it. This program is useful for systems doing many cryptographic tasks like VPN endpoints or GPG clients; it helps prevent the /dev/random device from being depleted and blocking reads.

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Recent releases

  •  01 May 2009 13:22

    Release Notes: There are major bugfixes. Users are urged to install this release. It also adds ALSA support.

    •  05 Jun 2008 17:15

      Release Notes: This release adds code that checks the quality of the random data; if it becomes bad, all data will be flushed until it is usable again.

      •  24 Nov 2002 15:05

        Release Notes: The sample-rate was lowered. The mixer-code was removed. The daemonise-function was changed to use daemon(...). The hashing-code was removed. Code that determines the amount of entropy in a buffer of data was added. The method of entropy-gathering was rewritten. Some code has been added to remove bias in the data.

        •  15 Sep 2002 16:05

          Release Notes: This release lets the daemon wait until the kernel signals that the lower threshold in /proc/sys/kernel/random/write_wakeup_threshold (number of bits) has been reached, then starts adding until the value of /proc/sys/kernel/random/poolsize (in bytes) has been reached. After a timeout, some entropy is still added (i.e.--wait), just like in version 0.0.0. The signals don't cause problems anymore with reading audio from the sound card.

          •  12 Sep 2002 14:24

            Release Notes: It is now possible to stop logging by sending SIGUSR2. Logging can be resumed by sending SIGUSR1.

            Recent comments

            11 Sep 2002 04:41 judoka1971

            Re: TODO: Circuit for white noise generator, powered by keyboard socket

            > Does anyone have a diagram for a circuit
            > like mentioned in the TODO file?
            > I.e.: Circuit for white noise generator,
            > powered by keyboard socket.
            >


            Could this idea work?
            http://groups.google.com/groups?q=white+noise+generator+circuit&hl=nl&lr=&ie=UTF-8&oe=UTF-8&selm=CDI91G.Ln9%40bernina.ethz.ch&rnum=5

            (must work at 5V and give input suitable for SB-like card)

            10 Sep 2002 10:08 judoka1971

            TODO: Circuit for white noise generator, powered by keyboard socket
            Does anyone have a diagram for a circuit like mentioned in the TODO file?
            I.e.: Circuit for white noise generator, powered by keyboard socket.

            15 Aug 2001 00:38 damienmill

            Re: gone
            It should be back now. Sorry.

            10 Apr 2001 10:04 fvh

            gone
            It looks like the page of that program is gone.
            Same thing for the program itself.
            Luckily I had the tarball on my system.
            I've dropped it on my site.
            URL: http://www.vanheusden.com/mirrors/.

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