Blockchain Academy
We'll get together for networking with people interested in Blockchain including developers and anyone curious about Blockchain.


Ethereum constitutes a state by an object called Account, and this state continues to change and is written to the block. Here, Account has 20 bytes of Address and State Transition, and Account has two kinds of Contract Accounts like Externally Owned Account (EOA) and Smart Contract like normal user account. Account consists of the following four fields.

  • Nonce: A kind of counter concept that allows each transaction to be processed only once. In the case of EOA, it indicates the number of transactions sent by the corresponding EOA. In case of CA, it means the number of contracts generated by this CA.
  • Ether Balance: Current account balance of the account
  • Contract Code: This is the code to be executed by the account. In case of EOA, it is treated as an empty string.
  • Storage: This is the storage space of the account, which is empty by default.

EOA is an account controlled by a private key and can not store code. It can send and receive Ether between EOAs like a normal user's account or a Bitcoin wallet, and also can create a smart contract and send transactions to a smart contract. The process of creating a public key using a private key of random value using the ECDSA algorithm and generating an address from the public key is the process of creating the EOA.