EIP-6049 is an Ethereum Improvement Proposal that proposes to deprecate the existing "SELFDESTRUCT" opcode in Ethereum and replace it with a new opcode called "halt", as part of the Shanghai Upgrade. ^[1]

Overview

On November 27th, 2022, EIP-6049 was created to improve the security and reliability of smart contracts in Ethereum by deprecating the problematic SELFDESTRUCT opcode and replacing it with a more secure and controlled function called "halt".

The self-destruct opcode allows a smart contract to destroy itself and return any remaining funds to a designated recipient. However, it has several issues that make it problematic for use in certain scenarios. ^[2]

One of the main issues with self-destruct is that it can be called by anyone, not just the owner of the contract. This can lead to situations where a malicious actor can destroy a contract and cause the owner to lose all of their funds. Additionally, self-destruct has an unbounded cost, meaning that it can be used to consume large amounts of gas and create denial-of-service attacks. ^[3]

The proposed "halt" opcode is intended to address these issues by providing a safer and more controlled way for contracts to self-destruct. Unlike self-destruct, halt can only be called by the contract owner and has a fixed gas cost. This will make it harder for attackers to abuse the function and create attacks that consume large amounts of gas and in turn, provide developers with greater control over their contracts and reduce the risk of attacks that can cause widespread damage to the Ethereum network. ^[2][3]