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ICONOMI(ICN)

Token
0x27cfa9ea91bd...549ea76f894b
DAO ForkContract #25KExact Bytecode MatchEdit this contract
Deployed October 14, 2016 (9 years ago)Block 2,435,659

A fixed-supply token with transfers and third-party allowances, deployed October 2016.

DAO Fork 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

By late 2016 ERC-20 had settled the interface a token was expected to answer, and the ethereum.org tutorial was still where most people copied one from. OpenZeppelin's contracts were not yet the default, so the code behind a token of this period is usually the tutorial's, with the constructor arguments changed and nothing else.

Token Information
Token Name
ICONOMI
Symbol
ICN
Decimals
18
Key Facts
Deployment Block
2,435,659
Deployment Date
Oct 14, 2016, 04:32 AM
Code Size
2.3 KB
Gas at Deploy
866,798

Description

A token from the ethereum.org tutorial. Balances sit in a public balanceOf mapping and transfer(to, value) moves them, throwing rather than returning false when the sender is short and checking the recipient's balance for overflow before adding to it. An allowance mapping lets a holder authorise another address to spend a limited amount through transferFrom. ApproveAndCall sets the allowance and calls receiveApproval on the spender in the same transaction, so a spending contract learns of its allowance at the moment it is granted. There is no owner and no way to create further units: the supply written at deployment is the whole supply. It was deployed as ICONOMI, with the symbol ICN and an opening supply of 100,000,000,000,000,000,000,000,000 base units at 18 decimal places.

Source Verified

Exact bytecode match(2,345 bytes)
Compiler: v0.4.0+

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

Bytecode Overview

Opcodes2,345
Unique Opcodes190
Jump Instructions123
Storage Operations45

External Links

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