bytecode-utils

Decode the CBOR encoded data at the end of an Ethereum contract's bytecode.

Install

yarn add @ethereum-sourcify/bytecode-utils

Usage

Solidity Contracts

import { decode, AuxdataStyle } from "@ethereum-sourcify/bytecode-utils";

const bytecodeRaw = "0x60806040526004361061003f5760003560e01...7265206c656e677468a2646970667358221220dceca8706b29e917dacf25fceef95acac8d90d765ac926663ce4096195952b6164736f6c634300060b0033"

// For Solidity contracts
decode(bytecodeRaw, AuxdataStyle.SOLIDITY);

Result example

{
  "ipfs": "QmdD3hpMj6mEFVy9DP4QqjHaoeYbhKsYvApX1YZNfjTVWp",
  "solcVersion": "0.6.11",
  "experimental": true,
  "bzzr0": "...",
  "bzzr1": "..."
}

Vyper Contracts

import { decode, getAuxdataStyle } from "@ethereum-sourcify/bytecode-utils";

const vyperBytecodeRaw = "0x..."; // Your Vyper contract bytecode

// For Vyper contracts
decode(vyperBytecodeRaw, getAuxdataStyle("Vyper", "0.4.1"));

Result example

{
  "integrity": "...",
  "runtimeSize": 1234,
  "dataSizes": [32, 64, 128],
  "immutableSize": 256,
  "vyperVersion": "0.3.10"
}

Vyper Version Compatibility Notes

Different Vyper compiler versions use different auxdata formats:

• <0.3.4: no CBOR auxdata
• 0.3.4: CBOR map {"vyper": [0, 3, 4]} with no length footer
• 0.3.5-0.3.9: CBOR map {"vyper": [...]} plus length footer
• 0.3.10-0.4.0: CBOR array [runtimeSize, dataSizes, immutableSize, {"vyper": [...]}]
• >=0.4.1: CBOR array [integrity, runtimeSize, dataSizes, immutableSize, {"vyper": [...]}]