token (miner)

Token

0xa5192cd81bd0...5dd983968a27

HomesteadContract #19KExact Bytecode MatchEdit this contract

Deployed June 17, 2016 (10 years ago)Block 1,718,272

A mineable subcurrency where claimMiningReward() mints 1 token to block.coinbase once per block. Deployed Jun 16 2016.

Homestead EraVerified Source

Key Facts

Deployer

0x778018...5ae7a7

Deployment Block

1,718,272

Deployment Date

Jun 17, 2016, 06:43 AM

Code Size

352.0 B

Gas at Deploy

170,976

Transactions by Year

20161

Deployment Transaction: 0xeee5380c48c6eb67...f4f04eafeb582b13

Description

An early proof-of-work mining mechanic implemented in Solidity. The claimMiningReward() function mints 1 token to block.coinbase (the address of the miner who produced the current block), but only once per block number — preventing multiple claims in a single block.

This pattern extends the classic ethereum.org coin tutorial with a mining layer: tokens are distributed to miners in proportion to their block production, creating a mineable ERC-20-style token before the ERC-20 standard was formalized.

The miningReward mapping records which address claimed each block's reward (mapping(uint => address)), functioning as both a guard against double-claiming and a historical ledger of which miner earned each block.

Deployed June 16 2016 — six days after solc v0.3.3 was released (June 10 2016). Almost certainly compiled with the latest available version.

Compiler discovery: Native C++ solc v0.1.5–v0.2.1 all produce 340 bytes due to aggressive bool-return deduplication. The JS emscripten build of v0.3.3 preserves ISZERO ISZERO canonicalization and separate bool return paths, yielding the correct 352 bytes.

Source Verified

SolidityExact bytecode match(352 bytes)

Compiler: soljson

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Historian Categories

Token

Heuristic Analysis

The following characteristics were detected through bytecode analysis and may not be accurate.

Detected Type: Token

Has ERC-20-like patterns

Homestead Era

The first planned hard fork. Removed the canary contract, adjusted gas costs.

Block span: 1,150,000 — 1,919,999

March 14, 2016 — July 20, 2016

Bytecode Overview

Opcodes352

Unique Opcodes88

Jump Instructions15

Storage Operations13

Verified Source Available

Source verified through compiler archaeology and exact bytecode matching.

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Show source code (Solidity)

contract token {
    mapping (address => uint) public coinBalanceOf;
    mapping (uint => address) miningReward;
    event CoinTransfer(address sender, address receiver, uint amount);

    function token(uint supply) {
        coinBalanceOf[msg.sender] = supply;
    }

    function sendCoin(address receiver, uint amount) returns(bool sufficient) {
        if (coinBalanceOf[msg.sender] < amount) return false;
        coinBalanceOf[msg.sender] -= amount;
        coinBalanceOf[receiver] += amount;
        CoinTransfer(msg.sender, receiver, amount);
        return true;
    }

    function claimMiningReward() {
        if (miningReward[block.number] == 0) {
            coinBalanceOf[block.coinbase] += 1;
            miningReward[block.number] = block.coinbase;
        }
    }
}