/lurch

Lurch is an Ethereum VM para-virtualization (ish) written in EVM bytecode.

Primary LanguageAssemblyMIT LicenseMIT

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Lurch VM

Lurch is an EVM implementation written in EVM, allowing eval functionality for smart contracts.

Uses

Arbitrary Contract Size

By using a Merkle Root, a contract can be broken into many smaller pieces. when executing one, simply supply the Merkle-proof and runtime bytecode, which can be verified before execution.

Optionally, contracts may have hidden (non-public) functions, which can be part of the Merkle-tree, but kept secret until (or if) needed. This may be useful for additional and complex recovery methods on contract wallets.

Hooking

The EVM makes it simple to swap out, extend or intercept any EVM operation:

  • Change storage slot based on caller or bytecode (hijack SSTORE and SLOAD)
  • Upgradable Wisps can have self-destruct-safe storage (forward SSTORE and SLOAD to external contract)
  • Hijack precompiles (or add new precompiles) (hijack CALL and ilk)
  • Allow arbitrary read-only code execution in your contraxct (revert on state changing opcodes)
  • Alter the runtime environment, such as provide alternate sources of BALANCE, CALLER, ORIGIN, etc.

Counter-Facutal Verification

No need to deploy a contract during a challenge, simply simulate the contract's execution without needing to deploy it

Links

ABI

// Note: You will need to replace /any/ with your result
//       type, if you wish the JavaScript to automatically
//       parse the result.
function eval(bytes bytecode, bytes calldata) returns (any)

Example

const { ether } = require("ethers");

// Connect to mainnet
const probider = ethers.utils.getDefautlProvider();

// Depending on your bytecode, change the return type
const iface = new ethers.Interface(["function eval(bytes, bytes) view returns (uint)"]);
const data = iface.encodeFunctionData("eval", [
  "0x602a60005260206000f3",   // Bytecode
  "0x"                        // Calldata
])

// Call lurch.eth with the encoded bytecode and calldata
provider.call({ to: "lurch.eth", data: data })
// 0x000000000000000000000000000000000000000000000000000000000000002a

License

MIT License.