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ERC20

ERC20 is a technical standard used for smart contracts on the Ethereum blockchain for implementing tokens [1]. ERC stands for Ethereum Request for Comment, and 20 is the number that was assigned to this request.

History

ERC20 was proposed on November 19, 2015 by Fabian Vogelsteller[2]. It defines a common list of rules that an Ethereum token has to implement, giving developers the ability to program how new tokens will function within the Ethereum ecosystem. This token protocol became popular with crowdfunding companies working on initial coin offering (ICO) cases.[3]

Today

As of January 2018, there were more than 21,000 ERC20 token contracts.[4] Among the most successful ERC20 token sales are EOS, Bancor, Qash, and Bankex, raising over $70 million each.[5]

Functions

ERC20 token has the following method-related functions:

The specific wording of the function is followed by a clarification of what it does, in [brackets]

  1. totalSupply [Get the total token supply]
  2. balanceOf(address _owner) constant returns (uint256 balance) [Get the account balance of another account with address _owner]
  3. transfer(address _to, uint256 _value) returns (bool success) [Send _value amount of tokens to address _to]
  4. transferFrom(address _from, address _to, uint256 _value) returns (bool success)[Send _value amount of tokens from address _from to address _to]
  5. approve(address _spender, uint256 _value) returns (bool success) [Allow _spender to withdraw from your account, multiple times, up to the _value amount. If this function is called again it overwrites the current allowance with _value]
  6. allowance(address *_owner*, address *_spender*) constant returns (uint256 remaining) [Returns the amount which _spender is still allowed to withdraw from _owner]

Events format:

  1. Transfer(address indexed _from, address indexed _to, uint256 _value). [Triggered when tokens are transferred.]
  2. Approval(address indexed _owner, address indexed _spender, uint256 _value)[Triggered whenever approve(address _spender, uint256 _value) is called.]

References

  1. ^ "ERC20 Token Standard - The Ethereum Wiki". Theethereum.wiki. Retrieved 30 August 2017. 
  2. ^ "ERC: Token standard #20". Github.com. Retrieved 13 April 2018. 
  3. ^ "Understanding the Ethereum ICO Token Hype". Blockchannel. 15 June 2017. Retrieved 30 August 2017. 
  4. ^ etherscan.io. "Etherscan Token Tracker Page". etherscan.io. Retrieved 2018-01-03. 
  5. ^ "Token Data | News, data and analytics for all ICO's and tokens". www.tokendata.io. Retrieved 2018-01-03.