After making the RFID RING we will make a Device that reads the data and writes the data about the owner of the ring . But if we keep everything inside the king ie bank password , Laptop password etc then its quit be challenging security reason so we have done a trick the main password is not saved in the ring and the password is also not saved in the reader device as actually there is password but no password its actually a algorithm that completed when right reader device and a right fuse with each other and password appear to authenticate the device and then disappear like it’s nowhere.so will will make a code for reader device that reads the ring and then add the algorithm in device with hat saved sata in ring and then it authenticate the device and then disappear like it never be there.Loos interesting and little bit science fiction.

Coding 

To install the required library, go to Arduino IDE and open library manager. Type MFRC522 in the search bar and select install. Now you can begin coding. 
Besides MFRC522, also include the library Servo in the code. While MFRC522.h enables the RFID reader module to read the RFID card, Servo.h equips the lock with a servo motor mechanism.
Next in the setup function, first, initialise the serial port for debugging to obtain the RFID number. Then initialise the SPI communication with the RFID module and set the servo pin number to drive the servo motor.
After this, create a loop function to read the RFID UUID number. Then convert the RFID UUID number to a string then our device that is unique reader device will adda a unique code with the UUID number to make the main password and then you use it to authenticate and then in action like sending it to open pc , of bank account or lock as of your voice here we test using the lock using servo moter movement 

Connection 

Connect the RFID with Arduino and servo/signal wire (yellow) to pin 9 (see pic).

Testing 

Power the Arduino and servo motor. Now try putting a random RFID card or tag into the lock. When nothing happens, then try with another. If that enables the servo motor to unlock the door, then it means you have entered the correct RFID tag.  
Congrats!! Your RFID smart lock is ready. 
 Download Code