I am thinking about storing secret in blockchain. Although there is some specific blockchain dealing with it, I would like to see the feasibility in ethereum.

The idea is to store the secret as a state variable in encrypted format and the accessibility of this variable value is restricted to someone only. My question is, since blockchain is open and everyone, if someone is really skillful then he/she could read the value of the every variable. Do you think, or what is needed to do further, to make the value of the state variable secured enough?

CodePudding user response：

People who own the machine running an EVM full node will have access to that variable. That accessibility limit is pointless in regards of keeping the data secret.

You could store encrypted data on-chain. But you need to keep the decryptor off-chain. E.g. you AES-encrypt a piece of data and post it on-chain, but you keep hold to the private key.

I should point out that an ethereum wallet, aka a secp256k1 keypair is capable of data en/decryption. You can encrypt data using public key, post it on-chain, and later fetch then decrypt with your private key, which is of course off-chain. Read more here.