How to avoid user to get metadata from non-minted ERC721 token?

Question

I'm building ERC721 and ERC1155 tokens but I have something I didn't understand..

My Tokens represent characters with attributes, where every attributes have a different rarity. So every character are more or less valuable based on their randomly generated attributes.

Metadata are stored into a IPFS buckets and the URL is ipfs://{Bucket_CID}/{tokenID}.json so, knowing the CID (from a previously generated token) everyone can go and look at every "next to generate token" and know every attributes it'll have and so the rarity... It's not fair, nobody will mint a common token and everyone will wait for a legendary one to mint.

How can I avoid that ?

One solution I have in mind is to hide them and reveal the CID only when every token are minted.. But it's not a real solution cause you cannot use them (example in a game) if all character are not mint, and I want to generate a very large number to offer everyone to get a new character, even if the game was started months ago..

Answer 1

Your choices are either

1. Hide the metadata (which means you could tell your friends which are the good ones and they could rush to get it); or
2. Publish the metadata and so everybody knowns

I just published on article on these different strategies at https://blog.phor.net/2022/02/04/Randomization-strategies-for-NFT-drops.html