token

Token

0xf30bf3dcb1fa...95fce48f7db2

FrontierContract #135Source VerifiedEdit this contract

Bytecode verified via sibling

This contract shares identical runtime bytecode with token (0xdbb576b5...) which has been verified through compiler archaeology.

Deployed August 10, 2015 (11 years ago)Block 63,925

The Frontier Guide's Coin tutorial contract: a pre-ERC-20 token with coinBalanceOf, sendCoin and a CoinTransfer event.

Frontier EraVerified Source

Historical Significance

The Frontier Guide's Coin contract was the standard worked example for issuing a currency on Ethereum, published more than a year before ERC-20 existed. It shows the pre-standard vocabulary the ecosystem used at the time: coinBalanceOf rather than balanceOf, sendCoin rather than transfer, and a CoinTransfer event rather than Transfer. Contracts like this are the direct ancestors of the token standard that replaced them.

Context

Deployed 2015-08-10 by 0xc70ba22fe446a85a247bf85bad1addf3ddaf62e9. Thirty-five byte-identical copies of this runtime appear in the Ethereum History archive as undocumented Frontier contracts, deployed by ten distinct addresses between 2015-08-08 and 2015-09-21. One address accounts for twenty of them; the remaining fifteen are spread across nine others, consistent with a mix of repeated experimentation and independent readers working through the same tutorial.

Key Facts

Deployer

0xc70ba2...af62e9

Deployment Block

63,925

Deployment Date

Aug 10, 2015, 01:15 PM

Code Size

495.0 B

Gas at Deploy

177,080

Deployment Transaction: 0x70cc4cdf696b8356...a8b4be6250a7d0d1

Description

A minimal pre-standard token. The constructor credits the deployer with the supply argument, falling back to 10000 via the old Solidity expression (supply || 10000). sendCoin(address,uint256) returns false instead of reverting when the sender's balance is short, debits and credits two entries of the public coinBalanceOf mapping, and emits CoinTransfer. The runtime is 495 bytes and dispatches two selectors: sendCoin(address,uint256) at 0x90b98a11 and the mapping getter coinBalanceOf(address) at 0xbbd39ac0. There is no allowance mechanism, no total supply accessor and no owner privilege.

Source Verified

Etherscan verified

Heuristic Analysis

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

Detected Type: Token

Has ERC-20-like patterns

Frontier Era

The initial release of Ethereum. A bare-bones implementation for technical users.

Block span: 0 — 1,149,999

July 30, 2015 — March 14, 2016

Bytecode Overview

Opcodes495

Unique Opcodes76

Jump Instructions13

Storage Operations8

Verified Source Available

Source verified on Etherscan.

Verified on Etherscan

Show source code (Solidity)

contract token { 
    mapping (address => uint) public coinBalanceOf;
    event CoinTransfer(address sender, address receiver, uint amount);
    function token(uint supply) {
        coinBalanceOf[msg.sender] = (supply || 10000);
    }
    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;
    }
}