To prevent the misuse of Aadhaar Card Biometric details, UIDAI allows you to lock and unlock it temporarily. Biometric information includes iris, fingerprints and the facial photograph. After locking the biometrics, you won't be able to use it for authentication purposes, till it is unlocked.
You should register your mobile number with Aadhaar, to lock/unlock your Aadhaar card biometrics. If you haven't registered your mobile number with Aadhaar, you can register it by visiting the nearest Aadhaar Enrolment Centre.
Steps to lock your Aadhaar card biometrics
Step 1: You should go to the UIDAI website and click on the 'Lock/Unlock Biometrics' option, under the 'Aadhaar Services' section.
Step 2: After you click on Lock/Unlock Biometrics, you will be redirected to a separate page called Lock/Unlock Biometrics. There, you will have to enter your 12-digit Aadhaar number and the security code in the space box given. Once you enter all this information, you will receive an OTP on your registered mobile number. You should enter the OTP in the space box and click Login.
Step 3: Once you log in, you will be asked to enter a security code to verify, if you are human and not a software. After entering the code, you need to click on enable.
Once your Aadhaar card biometric details are locked, The UIDAI will display the message "Congratulations! Your Biometrics are locked. You will not be able to authenticate using your fingerprints or iris. You can unlock biometrics temporarily for any authentication requirements. You can also disable the Locked Biometrics, but before that, you will be required to login using your Aadhaar."