Frontier Coin — Bytecode Verification

Proof of source code for two identical Frontier-era Ethereum contracts:

• 0xFF2947b1851bB16a7C8E71C6a8458D29600F9D6a — deployed Sep 21 2015 (block ~117,000 era)
• 0x522A493D563B0189c76877382b33F4c8C842922c — deployed Sep 22 2015

Both contracts have identical runtime bytecode (1648 bytes). This repo reproduces that bytecode exactly from source.

Contract

A Frontier-era subcurrency (coin) implementing a dual-send pattern: direct transfers plus exchange-authorized transfers. Based on the early Ethereum subcurrency tutorial but with:

• bytes32 name field (not string) — pre-string-encoding era
• Two send() overloads: basic and exchange-delegated
• All non-view functions return uint (0=fail, 1=success) — no reverts or booleans
• CoinTransfer and CoinIssue events (non-standard, pre-ERC-20)
• Exchange-authorized send: msg.sender must equal the exchange parameter — prevents unauthorized on-behalf transfers

Compiler

Field	Value
Compiler	soljson-v0.1.1+commit.6ff4cd6.js
Build	Emscripten/JavaScript (not native C++)
Optimizer	OFF (default, no --optimize)
Runtime size	1648 bytes

Download from: https://binaries.soliditylang.org/bin/soljson-v0.1.1+commit.6ff4cd6.js

Note: The native C++ build of v0.1.1 (commit 858e7b8) produces different bytecode due to different getter ordering from pointer comparison (set<Declaration*> uses pointer addresses, which differ between JS heap and C++ heap allocations). The emscripten JS build is required for an exact match.

Verification

# Download compiler
curl -O https://binaries.soliditylang.org/bin/soljson-v0.1.1+commit.6ff4cd6.js

# Verify
node verify.js

Expected output: ✅ EXACT MATCH — bytecode verified!

Key Insights

1. Emscripten build required — getter ordering (balance before issuer before name) is determined by JS heap allocation order, not C++ set<> pointer ordering
2. bytes32 public name — not string; just a 32-byte SLOAD, no dynamic encoding overhead
3. PUSH29/DIV dispatch — the 2015 selector dispatch style (no EXP shorthand); consistent with no-optimizer flag
4. Exchange pattern — send(address, uint, address exchange) requires the caller to BE the exchange; protects against unauthorized delegation
5. Storage layout: slot 0 = balance mapping, slot 1 = issuer address (packed), slot 2 = name (bytes32)

Files

• Coin.sol — Solidity source
• runtime.hex — Expected runtime bytecode (1648 bytes)
• verify.js — Verification script