/** * @file * Random number generator (RNG) module documentation file. * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * * This file is part of mbed TLS (https://tls.mbed.org) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ /** * @addtogroup rng_module Random number generator (RNG) module * * The Random number generator (RNG) module provides random number * generation, see \c ctr_dbrg_random(). * * The block-cipher counter-mode based deterministic random * bit generator (CTR_DBRG) as specified in NIST SP800-90. It needs an external * source of entropy. For these purposes \c mbedtls_entropy_func() can be used. This is * an implementation based on a simple entropy accumulator design. * * The other number generator that is included is less strong and uses the HAVEGE * (HArdware Volatile Entropy Gathering and Expansion) software heuristic * which considered unsafe for primary usage, but provides additional random * to the entropy pool if enables. * * \* Meaning that there seems to be no practical algorithm that can guess * the next bit with a probability larger than 1/2 in an output sequence. * * This module can be used to generate random numbers. */