Mastering Blockchain Programming with Solidity

Avoid sharing a secret on-chain

Ethereum is a public blockchain; hence, all the transaction data is visible to everyone. To execute a function on a contract, a user has to sign the function data from their EOA and send it to the Ethereum blockchain. In this process, the signed data contains the first four bytes of the function signature followed by the function arguments. This data is visible, and anyone can see the function definition as well, if the code of the contract is published on the block explorer.

If you have a contract that requires confidential data to be sent, it would be visible to everyone, and would not remain private when a transaction is initiated. As the Ethereum blockchain processes transactions slowly, you can see the ...