2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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23 * @file util/crypto_random.c
24 * @brief functions to gather random numbers
25 * @author Christian Grothoff
28 #include "gnunet_common.h"
29 #include "gnunet_crypto_lib.h"
33 * @return a random value in the interval [0,i[.
36 GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode,
39 #ifdef gcry_fast_random_poll
40 static unsigned int invokeCount;
44 GNUNET_assert (i > 0);
46 if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
48 /* see http://lists.gnupg.org/pipermail/gcrypt-devel/2004-May/000613.html */
49 #ifdef gcry_fast_random_poll
50 if ((invokeCount++ % 256) == 0)
51 gcry_fast_random_poll ();
53 gcry_randomize ((unsigned char *) &ret,
60 ret = i * ((double) RANDOM () / RAND_MAX);
69 * Get an array with a random permutation of the
71 * @param mode GNUNET_RANDOM_QUALITY_STRONG if the strong (but expensive)
72 * PRNG should be used, GNUNET_RANDOM_QUALITY_WEAK otherwise
73 * @param n the size of the array
74 * @return the permutation array (allocated from heap)
77 GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n)
84 GNUNET_assert (n > 0);
85 ret = GNUNET_malloc (n * sizeof (unsigned int));
86 for (i = 0; i < n; i++)
88 for (i = 0; i < n; i++)
90 x = GNUNET_CRYPTO_random_u32 (mode, n);
99 * Random on unsigned 64-bit values.
102 GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode,
107 GNUNET_assert (u > 0);
108 if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
110 gcry_randomize ((unsigned char *) &ret,
117 ret = u * ((double) RANDOM () / RAND_MAX);
125 * This function should only be called in testcases
126 * where strong entropy gathering is not desired
127 * (for example, for hostkey generation).
130 GNUNET_CRYPTO_random_disable_entropy_gathering ()
132 gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
136 /* end of crypto_random.c */