Vault

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract Vault {
  bool public locked;
  bytes32 private password;

  constructor(bytes32 _password) {
    locked = true;
    password = _password;
  }

  function unlock(bytes32 _password) public {
    if (password == _password) {
      locked = false;
    }
  }
}

Unlock the vault to pass the level!

💡 It’s important to remember that marking a variable as private only prevents
other contracts from accessing it. State variables marked as private and
local variables are still publicly accessible.
To ensure that data is private, it needs to be encrypted before being
put onto the blockchain. In this scenario, the decryption key should
never be sent on-chain, as it will then be visible to anyone who looks
for it. zk-SNARKs provide a way to determine whether someone possesses a secret parameter, without ever having to reveal the parameter.