Fabian Token — Bytecode Verification

Proof of source code for Fabian Token:

• 0xe274d18ef7b194a1edebb04cfe297cfe1489ef65 — deployed Oct 26 2015 (block 443,423)

Deployed by 0x9b22a80d5c7b3374a05b446081f97d0a34079e7f (Fabian Vogelsteller).

Contract

An early Ethereum token contract featuring a public balanceof mapping (lowercase) alongside an explicit balanceOf(address) function (camelCase). The constructor defaults to 10,000 supply if 0 is passed. Transfer events use LOG1 (non-indexed). This is a clean, minimal token implementation from October 2015 — before ERC-20 was formalized.

Compiler

Field	Value
Image	soljson-v0.1.5+commit.23865e39 (JavaScript, via node.js)
Optimization	OFF
Runtime size	625 bytes

Verification

Requires: node.js

./verify.sh

Expected: ⚠️ NEAR MATCH — 3 byte(s) differ (compiler layout ordering; all function bodies byte-identical)

The script downloads soljson-v0.1.5+commit.23865e39.js from binaries.soliditylang.org if not already present.

The 3-Byte Difference

The compiled output matches the on-chain bytecode at 622/625 bytes (99.5%). The 3 differing bytes are jump target addresses in the selector dispatch table — caused by a function body ordering difference in the compiler's internal representation. Both the transfer and balanceOf function bodies are byte-identical between compiled and on-chain.

This is a known artifact of early Solidity compilers (v0.1.x): the dispatch table's jump offsets shift when the compiler reorders function bodies internally. The source code, logic, and all opcodes match exactly.

Key Insights

1. Deployed by Fabian Vogelsteller — creator of the ERC-20 standard; this contract predates ERC-20 by over a year
2. Dual getter pattern — mapping (address => uint) public balanceof auto-generates balanceof(address) (0x3d64125b); the explicit balanceOf(address) function (0x70a08231) uses camelCase. Both selectors are live on-chain
3. Non-indexed Transfer event — LOG1 (single topic = signature hash only); ERC-20 later mandated indexed _from and _to (LOG3)
4. Constructor default — if (supply == 0) supply = 10000; — passing 0 initializes with 10,000 tokens
5. 99.5% bytecode match — the 3-byte difference is compiler dispatch ordering, not logic; all function bodies are byte-identical

Selectors

• 3d64125b → balanceof(address) — auto-getter from the public mapping (lowercase)
• 70a08231 → balanceOf(address) — explicit getter (camelCase)
• a9059cbb → transfer(address,uint256) — token transfer

Files

• MyToken.sol — Solidity source
• runtime.hex — On-chain runtime bytecode (625 bytes, from Etherscan)
• verify.sh — Verification script (requires node.js)