I want to make a smart contract that acts as an escrow for a decryption key : there is a file stored outside blockchain which is crypted. I'd like the smart contract to somehow keep the decryption key hidden from the beneficiary and then reveal to him when a condition is met...But I can't think of a good scheme to do that.
Someone suggested me to use a commit-reveal scheme : key is encrypted using symetric encryption, and encrypted again using asymetric encryption, then put on the blockchain. The password to decrypt is sent to the beneficiary when the condition is met. And then he can access to the asymetric encrypted data with his private key. But with this scheme I have to store the password outside blockchain and fetched it "myself" when the condition is met. Do you have a way to do it more trustlessly ?
(sorry for my english !!)