CTR_DRBG: explain the security strength and the entropy input length
Explain what how entropy input length is determined from the
configuration, and how this in turn determines the security strength.
Explain how the nonce is obtained during initialization.
diff --git a/include/mbedtls/hmac_drbg.h b/include/mbedtls/hmac_drbg.h
index bd05da3..f090ac4 100644
--- a/include/mbedtls/hmac_drbg.h
+++ b/include/mbedtls/hmac_drbg.h
@@ -1,10 +1,14 @@
/**
* \file hmac_drbg.h
*
- * \brief HMAC_DRBG (NIST SP 800-90A)
+ * \brief The HMAC_DRBG pseudorandom generator.
+ *
+ * This module implements the HMAC_DRBG pseudorandom generator described
+ * in <em>NIST SP 800-90A: Recommendation for Random Number Generation Using
+ * Deterministic Random Bit Generators</em>.
*/
/*
- * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ * Copyright (C) 2006-2019, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may