CTR_DRBG: make it easier to understand the security strength
Explain how MBEDTLS_CTR_DRBG_ENTROPY_LEN is set next to the security
strength statement, rather than giving a partial explanation (current
setting only) in the documentation of MBEDTLS_CTR_DRBG_ENTROPY_LEN.
* and #MBEDTLS_CTR_DRBG_ENTROPY_LEN is set to 24 or more (which is
* always the case unless it is explicitly set to a different value
* in `config.h`).
+ *
+ * Note that the value of #MBEDTLS_CTR_DRBG_ENTROPY_LEN defaults to:
+ * - \c 48 if the module #MBEDTLS_SHA512_C is enabled and the symbol
+ * #MBEDTLS_ENTROPY_FORCE_SHA256 is not enabled at compile time.
+ * This is the default configuration of the library.
+ * - \c 32 if the module #MBEDTLS_SHA512_C is disabled at compile time.
+ * - \c 32 if #MBEDTLS_ENTROPY_FORCE_SHA256 is enabled at compile time.
*/
/*
* Copyright (C) 2006-2019, Arm Limited (or its affiliates), All Rights Reserved
/** The amount of entropy used per seed by default.
*
* This is 48 bytes because the entropy module uses SHA-512
- * (`MBEDTLS_ENTROPY_FORCE_SHA256` is not set).
+ * #MBEDTLS_ENTROPY_FORCE_SHA256 is not set).
*
* \note See mbedtls_ctr_drbg_set_entropy_len() regarding what values are
* acceptable.
/** The amount of entropy used per seed by default.
*
* This is 32 bytes because the entropy module uses SHA-256
- * (the SHA-512 module is disabled or `MBEDTLS_ENTROPY_FORCE_SHA256` is set).
+ * (the SHA512 module is disabled or #MBEDTLS_ENTROPY_FORCE_SHA256 is set).
*
* \note See mbedtls_ctr_drbg_set_entropy_len() regarding what values are
* acceptable.
