diff --git a/examples/hello_world/main/main.cpp b/examples/hello_world/main/main.cpp
index 882c245..d831491 100644
--- a/examples/hello_world/main/main.cpp
+++ b/examples/hello_world/main/main.cpp
@@ -22,11 +22,11 @@
 
 // Copy the below hex string from the "Device EUI" field
 // on your device's overview page in the TTN console.
-const char *devEui = "48AC328FF03E9294";
+const char *devEui = "????????????????";
 
 // Copy the below two lines from bottom of the same page
-const char *appEui = "70B3D57ED000C6CD";
-const char *appKey = "C1ADB6821EF7E906BC51D981DF07CCC4";
+const char *appEui = "????????????????";
+const char *appKey = "????????????????????????????????";
 
 // Pins and other resources
 #define TTN_SPI_HOST      HSPI_HOST