1.5 KiB
| eip | title | author | discussions-to | status | type | category | created |
|---|---|---|---|---|---|---|---|
| 1052 | EXTCODEHASH opcode | Nick Johnson <arachnid@notdot.net> | https://ethereum-magicians.org/t/extcodehash-opcode/262 | Draft | Standards Track | Core | 2018-05-02 |
Abstract
This EIP specifies a new opcode, which returns the keccak256 hash of a contract's code.
Motivation
Many contracts need to perform checks on a contract's bytecode, but do not necessarily need the bytecode itself. For instance, a contract may want to check if another contract's bytecode is one of a set of permitted implementations, or it may perform analyses on code and whitelist any contract with matching bytecode if the analysis passes.
Contracts can presently do this using the EXTCODECOPY opcode, but this is expensive, especially for large contracts, in cases where only the hash is required. As a result, we propose a new opcode, EXTCODEHASH, which returns the keccak256 hash of a contract's bytecode.
Specification
A new opcode, EXTCODEHASH, is introduced, with number 0x3D. EXTCODEHASH takes one argument from the stack, and pushes the keccak256 hash of the code at that address to the stack.
Rationale
As described in the motivation section, this opcode is widely useful, and saves on wasted gas in many cases.
Backwards Compatibility
There are no backwards compatibility concerns.
Test Cases
TBD
Implementation
TBD
Copyright
Copyright and related rights waived via CC0.