diff --git a/docs/sts-final.pdf b/docs/sts-final.pdf
new file mode 100644
index 000000000..659f86969
Binary files /dev/null and b/docs/sts-final.pdf differ
diff --git a/p2p/secret_connection.go b/p2p/secret_connection.go
index 2cb524cf8..fb35e94b0 100644
--- a/p2p/secret_connection.go
+++ b/p2p/secret_connection.go
@@ -1,4 +1,6 @@
 // Uses nacl's secret_box to encrypt a net.Conn.
+// It is (meant to be) an implementation of the STS protocol.
+// See docs/sts-final.pdf for more info
 package p2p
 
 import (