Sound card as a random number source ??
Hello, when I read about hardware random number generators in this mailing list, I got one idea. Maybe it sounds crazy, but is it possible to use soundcard (SoundBlaster for example) as a source for really random numbers ? What if I connect the input line of the soundcard with some external source of noise, like FM receiver or Dolby Surround decoder (with built-in white noise generator) or tape recorder with blank (erased) tape. It is possible to sample the sound (noise) and use the sampled values as a random numbers ? And how much random is this source ? I tried to find some mentions about this method with altavista, but I didn't found anything. Bye PavelK -- **************************************************************************** * Pavel Korensky (pavelk@dator3.anet.cz) * * DATOR3 Ltd., Modranska 1895/17, 143 00 Prague 4, Czech Republic * * PGP key fingerprint: 00 65 5A B3 70 20 F1 54 D3 B3 E4 3E F8 A3 5E 7C * ****************************************************************************
-----BEGIN PGP SIGNED MESSAGE----- On Wed, 27 Nov 1996, Pavel Korensky wrote:
when I read about hardware random number generators in this mailing list, I got one idea. Maybe it sounds crazy, but is it possible to use soundcard (SoundBlaster for example) as a source for really random numbers ? What if I connect the input line of the soundcard with some external source of noise, like FM receiver or Dolby Surround decoder (with built-in white noise generator) or tape recorder with blank (erased) tape. It is possible to sample the sound (noise) and use the sampled values as a random numbers ? And how much random is this source ?
The LSBs of a recording of white noise or static should be pretty random. This should not be your only source of entropy as it's very easy for an attacker to bias the signals. If a one-way hash is applied to the output, it does make it much more difficult for an attacker to predict or influence the RNG. Mark - - -- finger -l for PGP key PGP encrypted mail prefered. 0xf9b22ba5 now revoked -----BEGIN PGP SIGNATURE----- Version: 2.6.3 Charset: noconv iQEVAwUBMpyV2SzIPc7jvyFpAQF8+ggAvRmoEaJqaK80j1RxKAp7Y44gjKxWlVPd pZlD+9P8bwoKQWZsMtKwG790d34ebmqnDVm6ES9mcp2HI1lqHrjDub6+dBPZyRjo +NPhdtRmLZ4iqzE9n0xAPTeMDJGQOmxKQHHJCzOmG5nio5OFPyJzAbZy9DkNiH8A n6xp+YBtC3gL7NKufMo0ehVW4XMM4EkwKmpIRMHM+m9Q8lhsQxzPr2+GaDQwo18s jkrEB4xK+wnscpsjz/c7hvNnutgdVjlCU7xhDuR+prb4dHwAqhraXDgrpZuhZC8M +Wyau1/11VXAfY03e8i/CiFrE4d6h9li95EopBuO6EfcjWZGgMH80g== =FSod -----END PGP SIGNATURE-----
Have you tried it without a mike plugged in? Always think about failure modes. Adam Pavel Korensky wrote: | Hello, | | when I read about hardware random number generators in this mailing list, I got | one idea. Maybe it sounds crazy, but is it possible to use soundcard | (SoundBlaster for example) as a source for really random numbers ? | What if I connect the input line of the soundcard with some external source of | noise, like FM receiver or Dolby Surround decoder (with built-in white noise | generator) or tape recorder with blank (erased) tape. It is possible to sample | the sound (noise) and use the sampled values as a random numbers ? And how much | random is this source ? | I tried to find some mentions about this method with altavista, but I didn't | found anything. | | Bye PavelK | | | -- | **************************************************************************** | * Pavel Korensky (pavelk@dator3.anet.cz) * | * DATOR3 Ltd., Modranska 1895/17, 143 00 Prague 4, Czech Republic * | * PGP key fingerprint: 00 65 5A B3 70 20 F1 54 D3 B3 E4 3E F8 A3 5E 7C * | **************************************************************************** | -- "It is seldom that liberty of any kind is lost all at once." -Hume
-----BEGIN PGP SIGNED MESSAGE----- On Wed, 27 Nov 1996, Adam Shostack wrote:
Have you tried it without a mike plugged in? Always think about failure modes.
Adam
Pavel Korensky wrote: | Hello, | | when I read about hardware random number generators in this mailing list, I got | one idea. Maybe it sounds crazy, but is it possible to use soundcard | (SoundBlaster for example) as a source for really random numbers ? | What if I connect the input line of the soundcard with some external source of | noise, like FM receiver or Dolby Surround decoder (with built-in white noise | generator) or tape recorder with blank (erased) tape. It is possible to sample | the sound (noise) and use the sampled values as a random numbers ? And how much | random is this source ? | I tried to find some mentions about this method with altavista, but I didn't | found anything. | | Bye PavelK |
Also, try reading from the PC speaker (this is usually a device on the sound card) without the speaker as input... the leads usually make enough of an antena to get all of your hardwares RF emissions, which should be a good source of random numbers. --Deviant PGP KeyID = E820F015 Fingerprint = 3D6AAB628E3DFAA9 F7D35736ABC56D39 The best way to accelerate a Macintoy is at 9.8 meters per second per second. -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMpz7YTCdEh3oIPAVAQGHgAf6A9uZgb5as6BKUaoEs+e4SPjdzZ0yzbEt nX7wNShQMIPD7VgwFhFQoKabvvf2jJchd6vBZqlvvaiOUqxf90IrUH3r1Ih+HcYl XkOzjXU9UlhwjzPlB+JJYH1o4m0lAfaB8R8Qx86cv+oZM8KfVaIOlgRu2q07dpIe 5CGBPZIB3ehg5wZwGwTwNRvT4RRzOwNa+JcoAViksN8yHuX70y9IgQAyFCXdQXeg 2H/lni/R8Q/Yi2OFGEzjn2km93rcb8xMvl+N98ilXOUnO8ahXmjf69DOWR43Yn8h VWW4dSQLdtjpP7reO06Vkeqxy4+SyKkB4gdCDw6F+eiR5ttr6mbEZA== =BytF -----END PGP SIGNATURE-----
Adam Shostack <adam@homeport.org> wrote:
Have you tried it without a mike plugged in? Always think about failure modes.
Adam
But there always can be some kind of test, like presampling and testing if the input is not dead. And of course some kind of hash algorithm must be applied to the sampled stream (MD5 ?). Bye PavelK -- **************************************************************************** * Pavel Korensky (pavelk@dator3.anet.cz) * * DATOR3 Ltd., Modranska 1895/17, 143 00 Prague 4, Czech Republic * * PGP key fingerprint: 00 65 5A B3 70 20 F1 54 D3 B3 E4 3E F8 A3 5E 7C * ****************************************************************************
participants (4)
-
Adam Shostack -
Mark M. -
Pavel Korensky -
The Deviant