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diff --git a/pipermail/pycrypto/2012q1/000534.html b/pipermail/pycrypto/2012q1/000534.html new file mode 100644 index 0000000..40f0a67 --- /dev/null +++ b/pipermail/pycrypto/2012q1/000534.html @@ -0,0 +1,121 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<HTML> + <HEAD> + <TITLE> [pycrypto] Use of Fortuna Algo / Seeding Randomness + </TITLE> + <LINK REL="Index" HREF="index.html" > + <LINK REL="made" HREF="mailto:pycrypto%40lists.dlitz.net?Subject=Re%3A%20%5Bpycrypto%5D%20Use%20of%20Fortuna%20Algo%20/%20Seeding%20Randomness&In-Reply-To=%3C20120113164401.GE5544%40rivest.dlitz.net%3E"> + <META NAME="robots" CONTENT="index,nofollow"> + <style type="text/css"> + pre { + white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ + } + </style> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="000533.html"> + <LINK REL="Next" HREF="000535.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[pycrypto] Use of Fortuna Algo / Seeding Randomness</H1> + <B>Dwayne C. Litzenberger</B> + <A HREF="mailto:pycrypto%40lists.dlitz.net?Subject=Re%3A%20%5Bpycrypto%5D%20Use%20of%20Fortuna%20Algo%20/%20Seeding%20Randomness&In-Reply-To=%3C20120113164401.GE5544%40rivest.dlitz.net%3E" + TITLE="[pycrypto] Use of Fortuna Algo / Seeding Randomness">dlitz at dlitz.net + </A><BR> + <I>Fri Jan 13 11:44:01 EST 2012</I> + <P><UL> + <LI>Previous message: <A HREF="000533.html">[pycrypto] reg current work in pycrypto +</A></li> + <LI>Next message: <A HREF="000535.html">[pycrypto] ANN: PyCrypto 2.5 released +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#534">[ date ]</a> + <a href="thread.html#534">[ thread ]</a> + <a href="subject.html#534">[ subject ]</a> + <a href="author.html#534">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE>On Sat, Nov 19, 2011 at 09:21:43AM -0800, Ben Smith wrote: +><i>Hi Everyone - +</I>><i> +</I>><i>I'm new to this package, so I'm sure I'm just dumb and it is obvious how +</I>><i>to do this. I want to use the fortuna algo in a simulation environment +</I>><i>(economics if anyone cares), my particular problem I'm trying to solve +</I>><i>would be biased using Mersenne twister (which seems to be the default +</I>><i>everyone uses), and fortuna seems to be the best option given the aspects +</I>><i>of randomness I care about for this problem. +</I>><i> +</I>><i>Anyhow, I want to seed fortuna with a file I have of atmospheric noise; I +</I>><i>haven't been able to find a doc specifying how to do this. +</I> +There's no supported way of doing this in PyCrypto. The best way to do +this, on Linux, would be to just write the data to /dev/random (or install +the "entropy-gathering daemon") and just use Crypto.Random normally. You +won't be able to tell the difference (and if you do, it's a security hole +that should be disclosed!) + +In theory, however, you could edit +Crypto/Random/_UserFriendlyRNG._EntropyCollector and add another +_EntropySource instance, then invoke the _EntropySource#feed method for +each atmospheric noise reading. + +Fortuna's accumulator has 32 pools, and the idea is to spread the entropy +uniformly across these pools. This is ultimately done by invoking +FortunaAccumulator#add_random_event, which takes the following parameters: + + - source_number + A fixed number (from 0 to 255) that is unique for each entropy + source. PyCrypto selects numbers starting from 255, so I suggest + that you use a numbers starting from 0. + - pool_number + Every time your entropy source invokes add_random_event, it should + increment this number, starting at 0, 1, ..., 31, and then wrapping + back to 0. + - data + The bytes representing your random data. + +Honestly, though, you should just use Crypto.Random as-is. If this is a +desktop computer with a keyboard and mouse, there's really no reason to +delve into the implementation of Crypto.Random. Your operating system +already has enough entropy to generate cryptographically-secure random +numbers that are indistinguishable from a truly random source. + +Cheers, +- Dwayne + +-- +Dwayne C. Litzenberger <<A HREF="http://lists.dlitz.net/cgi-bin/mailman/listinfo/pycrypto">dlitz at dlitz.net</A>> + OpenPGP: 19E1 1FE8 B3CF F273 ED17 4A24 928C EC13 39C2 5CF7 +</PRE> + + + + + + + + + + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="000533.html">[pycrypto] reg current work in pycrypto +</A></li> + <LI>Next message: <A HREF="000535.html">[pycrypto] ANN: PyCrypto 2.5 released +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#534">[ date ]</a> + <a href="thread.html#534">[ thread ]</a> + <a href="subject.html#534">[ subject ]</a> + <a href="author.html#534">[ author ]</a> + </LI> + </UL> + +<hr> +<a href="http://lists.dlitz.net/cgi-bin/mailman/listinfo/pycrypto">More information about the pycrypto +mailing list</a><br> +</body></html> |