Nectarium(NEP)

Token

0xb87b1d5331ca...1dbae3d6b9f4

HomesteadContract #17KExact Bytecode MatchEdit this contract

Deployed May 20, 2016 (10 years ago)Block 1,548,216

A hundred million units at sixteen decimal places, an unusually fine subdivision.

Homestead EraVerified Source

Historical Significance

This is the tutorial revision that added delegated spending, and it did it with approveAndCall: the allowance is set and the spender is called in the same transaction, so a contract learns about its allowance at the moment it is granted. It solved the problem ERC-20's plain approve leaves open, that a contract cannot notice an approval, and it was dropped from the standard anyway because it requires the spender to be a contract. The idea returned years later as ERC-777 and ERC-1363.

Context

Deployed in May 2016 during the Homestead era.

Token Information

Token Name

Nectarium

Symbol

NEP

Decimals

Key Facts

Deployer

0x54d2b3...808557

Deployment Block

1,548,216

Deployment Date

May 20, 2016, 01:42 AM

Code Size

1.6 KB

Gas at Deploy

659,202

Deployment Transaction: 0x9d24fa8df22b5164...0ed7d851744f54c2

Description

The decimals field is sixteen rather than the customary eighteen or two, so a single unit divides into ten quadrillion parts. The whole supply is credited to the deploying account at creation and nothing can mint more. Approvals go through approveAndCall, which records the allowance and then calls receiveApproval on the spender contract in the same transaction.

Source Verified

Exact bytecode match(1,680 bytes)

Compiler: v0.3.0+

View verification proof

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

Opcodes1,680

Unique Opcodes127

Jump Instructions79

Storage Operations30

Verified Source Available

Source verified through compiler archaeology and exact bytecode matching.

View Verification Proof

Show source code (Solidity)

// Submitted by EthereumHistory (ethereumhistory.com)
contract tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData); }

contract MyToken {
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {
        if (balanceOf[_from] < _value) throw;
        if (balanceOf[_to] + _value < balanceOf[_to]) throw;
        if (_value > allowance[_from][msg.sender]) throw;
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        allowance[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        return true;
    }

    string public standard = "Token 0.1";

    string public name;

    string public symbol;

    uint8 public decimals;

    uint256 public totalSupply;

    mapping (address => uint256) public balanceOf;

    mapping (address => mapping (address => uint256)) public allowance;

    event Transfer(address indexed from, address indexed to, uint256 value);

    function MyToken(uint256 initialSupply, string tokenName, uint8 decimalUnits, string tokenSymbol) {
        balanceOf[msg.sender] = initialSupply;
        totalSupply = initialSupply;
        name = tokenName;
        symbol = tokenSymbol;
        decimals = decimalUnits;
    }

    function transfer(address _to, uint256 _value) {
        if (balanceOf[msg.sender] < _value) throw;
        if (balanceOf[_to] + _value < balanceOf[_to]) throw;
        balanceOf[msg.sender] -= _value;
        balanceOf[_to] += _value;
        Transfer(msg.sender, _to, _value);
    }

    function approveAndCall(address _spender, uint256 _value, bytes _extraData) returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        tokenRecipient spender = tokenRecipient(_spender);
        spender.receiveApproval(msg.sender, _value, this, _extraData);
        return true;
    }

    function () {
        throw;
    }
}