diff --git a/core/net/mac/tsch/tsch-security.h b/core/net/mac/tsch/tsch-security.h
index 42f18e8d9..3fdf784c2 100644
--- a/core/net/mac/tsch/tsch-security.h
+++ b/core/net/mac/tsch/tsch-security.h
@@ -118,10 +118,24 @@
 typedef uint8_t aes_key[16];
 
 /********** Functions *********/
-
+/**
+ * \brief Return MIC length
+ * \return The length of MIC (>= 0)
+ */
 int tsch_security_mic_len(const frame802154_t *frame);
+
+/**
+ * \brief Protect a frame with encryption and/or MIC
+ * \return The length of a generated MIC (>= 0)
+ */
 int tsch_security_secure_frame(uint8_t *hdr, uint8_t *outbuf,
     int hdrlen, int datalen, struct asn_t *asn);
+
+/**
+ * \brief Parse and check a frame protected with encryption and/or MIC
+ * \retval 0 On error or security check failure (insecure frame)
+ * \retval 1 On success or no need for security check (good frame)
+ */
 int tsch_security_parse_frame(const uint8_t *hdr, int hdrlen, int datalen,
     const frame802154_t *frame, const linkaddr_t *sender, struct asn_t *asn);