I gave my Aadhaar card to a service provider for proving my identity. Can anyone harm me by knowing and misusing my Aadhaar number?

No. Just, by knowing your Aadhaar number, no one can harm you. It’s just like any other identity document such as passport, voter ID, PAN card, ration card, driving license, etc., that you have been using freely for decades with service providers. Aadhaar identity, instead, is instantly verifiable and hence more trusted. Also, as per the Aadhaar Act 2016, the Aadhaar card is required to be verified  either by in physical or electronic formby way of authentication or offline verification, or in such other form as may be specified. Verification is done through fingerprint, iris scan, OTP authentication, and QR code etc. Hence, it is near impossible to impersonate you if you use Aadhaar to prove your identity. People have been freely giving other identity documents such as passport, voter ID, PAN card, ration card, driving license, etc. But did they stop using these documents for the fear that somebody would use them to impersonate? No! They continue using them and if any fraud happens, the law enforcement agencies handle them as per law. The same logic will apply to Aadhaar. In fact, Aadhaar is more secure than many other identity documents, because unlike other IDs, Aadhaar is instantly verifiable through biometric and OTP authentication and QR code. Further, under the Aadhaar Act, 2016 stringent penalties, including fines and imprisonment are provided whenever a person misuses your Aadhaar number or tries to cause any harm to you.