pk_sign() now requires non-NONE md_alg for ECDSA
diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h
index b1fd884..57f9b48 100644
--- a/include/mbedtls/ecdsa.h
+++ b/include/mbedtls/ecdsa.h
@@ -52,6 +52,8 @@
/**
* \brief Compute ECDSA signature of a previously hashed message
*
+ * \note The deterministic version is usually prefered.
+ *
* \param grp ECP group
* \param r First output integer
* \param s Second output integer
@@ -70,8 +72,8 @@
#if defined(POLARSSL_ECDSA_DETERMINISTIC)
/**
- * \brief Compute ECDSA signature of a previously hashed message
- * (deterministic version)
+ * \brief Compute ECDSA signature of a previously hashed message,
+ * deterministic version (RFC 6979).
*
* \param grp ECP group
* \param r First output integer
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 14ac65e..8fda581 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -377,7 +377,8 @@
* \note If hash_len is 0, then the length associated with md_alg
* is used instead, or an error returned if it is invalid.
*
- * \note md_alg may be POLARSSL_MD_NONE, only if hash_len != 0
+ * \note For RSA, md_alg may be POLARSSL_MD_NONE if hash_len != 0.
+ * For ECDSA, md_alg may never be POLARSSL_MD_NONE.
*/
int pk_sign( pk_context *ctx, md_type_t md_alg,
const unsigned char *hash, size_t hash_len,