DRBG documentation: Relate f_entropy arguments to the entropy module
diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
index 6626024..5955079 100644
--- a/include/mbedtls/ctr_drbg.h
+++ b/include/mbedtls/ctr_drbg.h
@@ -179,6 +179,16 @@
* \brief This function seeds and sets up the CTR_DRBG
* entropy source for future reseeds.
*
+ * A typical choice for the \p f_entropy and \p p_entropy parameters is
+ * to use the entropy module:
+ * - \p f_entropy is mbedtls_entropy_func();
+ * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
+ * with mbedtls_entropy_init() (which registers the platform's default
+ * entropy sources).
+ *
+ * \p f_entropy is always called with a buffer size equal to the entropy
+ * length described in the documentation of mbedtls_ctr_drbg_set_entropy_len().
+ *
* You can provide a personalization string in addition to the
* entropy source, to make this instantiation as unique as possible.
*
diff --git a/include/mbedtls/hmac_drbg.h b/include/mbedtls/hmac_drbg.h
index f253b9a..bcecba9 100644
--- a/include/mbedtls/hmac_drbg.h
+++ b/include/mbedtls/hmac_drbg.h
@@ -122,6 +122,13 @@
*
* Set the initial seed and set up the entropy source for future reseeds.
*
+ * A typical choice for the \p f_entropy and \p p_entropy parameters is
+ * to use the entropy module:
+ * - \p f_entropy is mbedtls_entropy_func();
+ * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
+ * with mbedtls_entropy_init() (which registers the platform's default
+ * entropy sources).
+ *
* You can provide a personalization string in addition to the
* entropy source, to make this instantiation as unique as possible.
*