1) Is that a custom data (not a HID one)? If so, you can create a new characteristic and store the data in the GATT DB?
2) You can perform bonding operation in which the host device and its security details are stored in flash. Refer Bonding in BLE Datasheet.
Thanks Madhu Sudhan.
Its actually a simple 3x3 keypad matrix and all the 9 keys status (pressed/not pressed) stored in 2 bytes data. Its a keypad key press status, not exactly custom. So, I used the Report characteristic to store 2 bytes and did not create another characteristic. Is (dafault) report characteristic used for something else or I can use it as is?