What does Lock/Unlock Aadhaar mean?

To further strengthen your privacy and security, UIDAI has introduced a feature to lock and unlock your Aadhaar Number. After locking your Aadhaar Number, Authentication cannot be performed using Aadhaar Number. In that case you may use your Virtual ID to perform Authentication. This will prevent the misuse of your Aadhaar Number by anyone else. Unlocking your Aadhaar Number will resume the use of Aadhaar Number for Authentication.