Assuming you mean a way to keep your NFTs in your posession: safe.global multisig, with a few hardware wallets. If your keys get compromised, you can re-key the lock easily.

If you mean keeping the contents of an NFT private to holders, then something like Lit Protocol?

Building pods.media to help you collect conversations.

Building /bright-moments - minting onchain art IRL | /purple #15 | FID 129 #magikarp

Rome, Metropolitan City of Rome Capital, Italy

I think he’s referring to a physical lock that opens for the holder of a specific NFT