Vitalik Moose Factory Verification

Byte-for-byte bytecode verification for 0x42dd263af905666eff278d9c9602478407351457.

Field	Value
Contract	0x42dd263af905666eff278d9c9602478407351457
Network	Ethereum Mainnet
Block	2,284,575
Deployed	September 19, 2016
Deployer	0x1db3439a222c519ab44bb1144fc28167b4fa6ee6 (Vitalik Buterin dev address)
Compiler	Serpent 2.0.7 (serpent-compiler / ethereum_serpent-2.0.7)
Optimizer	N/A
Runtime match	✅ EXACT (293 bytes, after stripping 4 trailing dead bytes)

Verification

# Requires Docker with the serpent-compiler (Serpent 2.0.7) image built locally
./verify.sh

Note on Trailing Dead Bytes

Serpent 2.0.7 appends 4 dead bytes (5b6000f3 = JUMPDEST, PUSH1 0, RETURN) to every compiled output. The deployer stripped these before deploying, a common practice to save gas. The verify script accounts for this: compiled_runtime[:-4] matches on-chain exactly.

Building the Compiler

git clone https://github.com/ethereum/serpent
cd serpent
git checkout v2.0.7
pip install .
# Or build via Docker with the serpent-compiler Dockerfile

What This Contract Does

A CREATE factory contract that tests EVM CREATE mechanics and pre-computed deployment addresses.

1. Computes the pre-deployment address of a child contract using RLP([self, 0]) (pre-Spurious Dragon address derivation)
2. Checks the predicted address currently has no code (extcodesize == 0)
3. Deploys a child contract (moose.se) via create()
4. Calls moose() on the deployed child to verify it works
5. Validates both conditions with invalid() on failure
6. Emits a Lol event logging the extcodesize result and moose() return value

The child moose.se returns extcodesize(self) * codesize() — the product of its own runtime size and init code size — serving as a deployment sanity check.

This was Vitalik's exploration of factory patterns, pre-computed CREATE addresses, and external call verification in September 2016.

Source Files

• factory.se: The outer factory contract (compiled with Serpent 2.0.7)
• moose.se: The child contract (embedded as inline init code within factory.se)