diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
index 4db61d636..99da3db3f 100644
--- a/hostapd/hostapd.conf
+++ b/hostapd/hostapd.conf
@@ -1780,6 +1780,10 @@ own_ip_addr=127.0.0.1
 #	Tunnel-Password
 # 3 = ask RADIUS server during 4-way handshake if there is no locally
 #	configured PSK/passphrase for the STA
+#
+# The Tunnel-Password attribute in Access-Accept can contain either the
+# 8..63 character ASCII passphrase or a 64 hex character encoding of the PSK.
+#
 #wpa_psk_radius=0
 
 # Set of accepted key management algorithms (WPA-PSK, WPA-EAP, or both). The