PRIVATE BLOCKCHAIN

Description

This is a an implementation of a private blockchain. All the code can be found in the file simpleChain.js. The program can:

• instantiate a Blockchain class and persist the Genesis Block (first block of the given blockchain) in the LevelDB database
• add new subsequent blocks to the blockchain and persist them in the database
• get the block height of the blockchain
• get a block for a given block height
• validate a block
• validate the whole chain

Data Model

Class Block

Class that is represents every block and the information it contains, in the blockchain.

{   "hash" = "<SHA256 hash of the block>",
    "height" = "<can be considered as the number of the block>",
    "body" = "<data in the block>"),
    "time" = "<timestamp of the creation of the block>",
    "previousBlockHash" = "<hash of the previous block>"
}

Class Blockchain

Class that represents the blockchain. The class provides with the following functionalities:

• Persist blockchain data using LevelDB (level library)
• Add new blocks to the blockchain
• Get blocks from the blockchain
• Get block height from the blockchain
• Validate a single block
• Validate the blockchain (multiple blocks)

Database

The information of the blockchain is stored in a key-value database - LevelDB. The information representing an individual is stored the following way:

• key= block height (starts at 0 for the Genesis block (first block))
• value = string representing the block information

How to run

• Clone the project using: git clone https://github.com/ivivanov18/Private_Blockchain.git
• Run the command npm install to install the dependencies
• Run the program node simpleChain.js

To improve

• Refactor the code to separate the implementation of the Block, Blockchain, and code for testing in different files