https://devzone.nordicsemi.com/f/nordic-q-a/53059/how-does-softdevice-set-up-permissions-on-characteristics-example-makes-no-senseHere is the code snippet initializing the Heart Rate Measurement Characteristic in the BleHeartRateMonitor example: static uint32_t characteristic_init() { uint32_t error_code; ble_gatts_char_md_t char_md; ble_gatts_attr_md_t cccd_md; ble_gatts_attr_ten-USTelligent Community 13Fri, 11 Oct 2019 11:48:42 GMThttps://devzone.nordicsemi.com/thread/214590?ContentTypeID=1Fri, 11 Oct 2019 11:48:42 GMT137ad170-7792-4731-bb38-c0d22fbe4515:498ab5e5-4b71-4034-b82a-9da8349c1614Einar Thorsrud<p>Hi,</p> [quote user=""]How do I configure JUST the CCCD for secured write?[/quote] <p>You set the value of the&nbsp;cccd_write_access accordingly.</p> [quote user=""]How do I make sure the the HR measurement itself is NOT readable or writable?[/quote] <p>This is at least partially answered <a href="https://devzone.nordicsemi.com/f/nordic-q-a/53032/invalid_parameter-returned-when-setting-cccd-to-secure">here</a>. Essentially this is defined by the char_props, and since char_md in this code is memset to 0, anything you do not explicitly enable by setting it to 1 is disabled. Writing or reading is not allowed with this code, as you want.&nbsp;</p><div style="clear:both;"></div>