1 /** 2 * @file 3 * Random number generator (RNG) module documentation file. 4 * 5 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 6 * SPDX-License-Identifier: Apache-2.0 7 * 8 * Licensed under the Apache License, Version 2.0 (the "License"); you may 9 * not use this file except in compliance with the License. 10 * You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, software 15 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 16 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 17 * See the License for the specific language governing permissions and 18 * limitations under the License. 19 * 20 * This file is part of mbed TLS (https://tls.mbed.org) 21 */ 22 23 /** 24 * @addtogroup rng_module Random number generator (RNG) module 25 * 26 * The Random number generator (RNG) module provides random number 27 * generation, see \c mbedtls_ctr_drbg_random(). 28 * 29 * The block-cipher counter-mode based deterministic random 30 * bit generator (CTR_DBRG) as specified in NIST SP800-90. It needs an external 31 * source of entropy. For these purposes \c mbedtls_entropy_func() can be used. 32 * This is an implementation based on a simple entropy accumulator design. 33 * 34 * The other number generator that is included is less strong and uses the 35 * HAVEGE (HArdware Volatile Entropy Gathering and Expansion) software heuristic 36 * which considered unsafe for primary usage, but provides additional random 37 * to the entropy pool if enables. 38 * 39 * Meaning that there seems to be no practical algorithm that can guess 40 * the next bit with a probability larger than 1/2 in an output sequence. 41 * 42 * This module can be used to generate random numbers. 43 */ 44
