* files does not exist, create a new key and write it to the
* file. Caller must free return value. Note that this function
* can not guarantee that another process might not be trying
- * the same operation on the same file at the same time. The
- * caller must somehow know that the file either already exists
- * with a valid key OR be sure that no other process is calling
- * this function at the same time. If the contents of the file
+ * the same operation on the same file at the same time.
+ * If the contents of the file
* are invalid the old file is deleted and a fresh key is
* created.
*