Code

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.26;

contract onlyAdmin{
	string public currentAdminName = "Robbie";
	string adminPass = "qwerty";
	address adminAddress;
	
    constructor() {
        adminAddress = msg.sender;
    }
	
	modifier isAdmin(string memory passkey) {
		require(msg.sender == adminAddress, "Only Admin can update the name of Admin");
		require(keccak256(abi.encodePacked(adminPass)) == keccak256(abi.encodePacked(passkey)), "Password entered for Admin does not match");
		_;
	}

    // keccak256 hash the input string
    // abi.encodePacked(string) is used to encode the strings into bytes
	
	function updateAdmin(string memory newAdmin, string memory passkey) public isAdmin(passkey) {
		currentAdminName = newAdmin;
	}
	
	function updatePassword(string memory oldPass, string memory newPass) public isAdmin(oldPass) {
		adminPass = newPass;
	}
}