1 /** 2 * \file doc_rng.h 3 * 4 * \brief Random number generator (RNG) module documentation file. 5 */ 6 /* 7 * 8 * Copyright The Mbed TLS Contributors 9 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 10 */ 11 12 /** 13 * @addtogroup rng_module Random number generator (RNG) module 14 * 15 * The Random number generator (RNG) module provides random number 16 * generation, see \c mbedtls_ctr_drbg_random(). 17 * 18 * The block-cipher counter-mode based deterministic random 19 * bit generator (CTR_DBRG) as specified in NIST SP800-90. It needs an external 20 * source of entropy. For these purposes \c mbedtls_entropy_func() can be used. 21 * This is an implementation based on a simple entropy accumulator design. 22 * 23 * The other number generator that is included is less strong and uses the 24 * HAVEGE (HArdware Volatile Entropy Gathering and Expansion) software heuristic 25 * which considered unsafe for primary usage, but provides additional random 26 * to the entropy pool if enables. 27 * 28 * Meaning that there seems to be no practical algorithm that can guess 29 * the next bit with a probability larger than 1/2 in an output sequence. 30 * 31 * This module can be used to generate random numbers. 32 */ 33