Change cipher prototypes for GCM
diff --git a/include/polarssl/gcm.h b/include/polarssl/gcm.h
index 2bed342..dc058dc 100644
--- a/include/polarssl/gcm.h
+++ b/include/polarssl/gcm.h
@@ -146,7 +146,7 @@
* \param mode GCM_ENCRYPT or GCM_DECRYPT
* \param iv initialization vector
* \param iv_len length of IV
- * \param add additional data
+ * \param add additional data (or NULL if length is 0)
* \param add_len length of additional data
*
* \return 0 if successful
@@ -182,14 +182,14 @@
/**
* \brief Generic GCM finalisation function. Wraps up the GCM stream
- * and generated the tag. The tag can have a maximum length of
+ * and generates the tag. The tag can have a maximum length of
* 16 bytes.
*
* \param ctx GCM context
- * \param tag buffer for holding the tag
+ * \param tag buffer for holding the tag (may be NULL if tag_len is 0)
* \param tag_len length of the tag to generate
*
- * \return 0 if successful or POLARSSL_ERR_GCM_BAD_INPUT
+ * \return 0 if successful or POLARSSL_ERR_GCM_BAD_INPUT
*/
int gcm_finish( gcm_context *ctx,
unsigned char *tag,