diff --git a/build.py b/build.py
index a3b3c13b..0d4e24bc 100644
--- a/build.py
+++ b/build.py
@@ -86,6 +86,8 @@ with open(otakeyfile) as myfile:
         key, value = line.partition("=")[::2]
         mykeys[key.strip()] = str(value).strip()
 
+# usage of bintray: see https://github.com/r0oland/bintray-secure-ota
+
 # get bintray user credentials from ota key file
 user = mykeys["BINTRAY_USER"]
 repository = mykeys["BINTRAY_REPO"]
diff --git a/src/ota.cpp b/src/ota.cpp
index 07532c08..95d780f8 100644
--- a/src/ota.cpp
+++ b/src/ota.cpp
@@ -22,6 +22,7 @@
 using namespace std;
 
 const BintrayClient bintray(BINTRAY_USER, BINTRAY_REPO, BINTRAY_PACKAGE);
+// usage of bintray: see https://github.com/r0oland/bintray-secure-ota
 
 // Connection port (HTTPS)
 const int port = 443;