diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index c2144fb..ff85924 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -2415,21 +2415,22 @@
  *                          be unoccupied.
  * \param type              Key type (a \c PSA_KEY_TYPE_XXX value).
  * \param bits              Key size in bits.
- * \param[in] parameters    Extra parameters for key generation. The
+ * \param[in] extra         Extra parameters for key generation. The
  *                          interpretation of this parameter depends on
  *                          \c type. All types support \c NULL to use
  *                          the default parameters specified below.
- * \param parameters_size   Size of the buffer that \p parameters
- *                          points to, in bytes.
+ * \param extra_size        Size of the buffer that \p extra
+ *                          points to, in bytes. Note that if \p extra is
+ *                          \c NULL then \p extra_size must be zero.
  *
  * For any symmetric key type (a type such that
- * #PSA_KEY_TYPE_IS_ASYMMETRIC(\p type) is false), \c parameters must be
+ * #PSA_KEY_TYPE_IS_ASYMMETRIC(\p type) is false), \p extra must be
  * \c NULL. For asymmetric key types defined by this specification,
  * the parameter type and the default parameters are defined by the
  * table below. For vendor-defined key types, the vendor documentation
  * shall define the parameter type and the default parameters.
  *
- * Type | Parameter type | Meaning | Parameters used if `parameters == NULL`
+ * Type | Parameter type | Meaning | Parameters used if `extra == NULL`
  * ---- | -------------- | ------- | ---------------------------------------
  * `PSA_KEY_TYPE_RSA_KEYPAIR` | `unsigned int` | Public exponent | 65537
  *
@@ -2445,8 +2446,8 @@
 psa_status_t psa_generate_key(psa_key_slot_t key,
                               psa_key_type_t type,
                               size_t bits,
-                              const void *parameters,
-                              size_t parameters_size);
+                              const void *extra,
+                              size_t extra_size);
 
 /**@}*/
 
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index fce9e3c..a256ad7 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -2964,13 +2964,13 @@
 psa_status_t psa_generate_key( psa_key_slot_t key,
                                psa_key_type_t type,
                                size_t bits,
-                               const void *parameters,
-                               size_t parameters_size )
+                               const void *extra,
+                               size_t extra_size )
 {
     key_slot_t *slot;
     psa_status_t status;
 
-    if( parameters == NULL && parameters_size != 0 )
+    if( extra == NULL && extra_size != 0 )
         return( PSA_ERROR_INVALID_ARGUMENT );
 
     status = psa_get_empty_key_slot( key, &slot );
@@ -3010,10 +3010,10 @@
         int exponent = 65537;
         if( bits > PSA_VENDOR_RSA_MAX_KEY_BITS )
             return( PSA_ERROR_NOT_SUPPORTED );
-        if( parameters != NULL )
+        if( extra != NULL )
         {
-            const unsigned *p = parameters;
-            if( parameters_size != sizeof( *p ) )
+            const unsigned *p = extra;
+            if( extra_size != sizeof( *p ) )
                 return( PSA_ERROR_INVALID_ARGUMENT );
             if( *p > INT_MAX )
                 return( PSA_ERROR_INVALID_ARGUMENT );
@@ -3048,7 +3048,7 @@
             mbedtls_ecp_curve_info_from_grp_id( grp_id );
         mbedtls_ecp_keypair *ecp;
         int ret;
-        if( parameters != NULL )
+        if( extra != NULL )
             return( PSA_ERROR_NOT_SUPPORTED );
         if( grp_id == MBEDTLS_ECP_DP_NONE || curve_info == NULL )
             return( PSA_ERROR_NOT_SUPPORTED );