Suppose you are designing an access control system for a secure facility. The system uses $[4]$ keycards with embedded codes. There are $3$ security guards in the facility and each have a keycard that is encoded with a $3$ bit unique identifier. The keycards are shown below:

$010$

$110$

$000$

The access control system is only enabled from $8$:$00$ am to $3$:$00$ pm$.$ That means even if the guards try to enter the facility at night, the control system won't be able to give them access. Design a combinational circuit that has an active low enabler or inverted output that recognizes the unique identifier on the keycard and grants access only to authorized individuals using decoder and NAND gate. Show the truth table and logic circuit using decoder$$block$$diagram$.$