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+/**
+ * \file doc_rng.h
+ *
+ * \brief Random number generator (RNG) module documentation file.
+ */
+/*
+ *
+ * Copyright The Mbed TLS Contributors
+ * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+/**
+ * @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.
+ *
+ * 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.
+ */