Private variable on blockchain as password

Hey guys,

I'm onto a NFT project, and want the winner to see a password. What is best practice:
Safe a value on the blockchain and make it accessible only to the winners owner address (Is it readable for everyone because of the blockchain being public?). Or should I safe the value in the Frontend and make it accessible to the winner when he has won (Is it possible to read a value in the FrontEnd using ReactJS?). Thanks for your opinions :slight_smile: