|  | /** | 
|  | * @file | 
|  | * Random number generator (RNG) module documentation file. | 
|  | * | 
|  | *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved | 
|  | *  SPDX-License-Identifier: Apache-2.0 | 
|  | * | 
|  | *  Licensed under the Apache License, Version 2.0 (the "License"); you may | 
|  | *  not use this file except in compliance with the License. | 
|  | *  You may obtain a copy of the License at | 
|  | * | 
|  | *  http://www.apache.org/licenses/LICENSE-2.0 | 
|  | * | 
|  | *  Unless required by applicable law or agreed to in writing, software | 
|  | *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT | 
|  | *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 
|  | *  See the License for the specific language governing permissions and | 
|  | *  limitations under the License. | 
|  | * | 
|  | *  This file is part of mbed TLS (https://tls.mbed.org) | 
|  | */ | 
|  |  | 
|  | /** | 
|  | * @addtogroup rng_module Random number generator (RNG) module | 
|  | * | 
|  | * The Random number generator (RNG) module provides random number | 
|  | * generation, see \c mbedtls_ctr_drbg_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. | 
|  | */ |