Quark

This is my implementation of a blockchain - Quark.
You can experiment with it in the main.cpp file. Follow through this README file to check out the functionalities and brief implementations of the methods provided.

Compilation

meson build
cd build && meson compile

The main binary will be created in the build folder with name : "quark" after compiling with meson

BLOCK

Header:

Fields

- Previous Hash
- Timestamp
- Index

Data:

Fields

- Money Transfer
- Debtor
- Creditor

Method

- std:string toString() : Converts the data struct into a string

Methods:

• Constructor:

Block::Block(long long unsigned int& index, utils::Data& data, unsigned char*& prevHash){
    this->index     = index;
    this->data      = data;
    this->timestamp = utils::getTimestamp();
    strcpy((char*)this->prevHash, (char*)prevHash);
    this->calculateHash();
    //strcpy((char*)this->hash, (char*)hash); 
}

• Calculate Hash:

bool Block::calculateHash(){
    // Calculate hash and set it to hash variable
    std::string stringStruct = this->data.toString();
    unsigned long long int len = strlen(stringStruct.c_str());
    SHA256((unsigned char*)stringStruct.c_str(), len, this->hash);
    return true;
}

BLOCKCHAIN

Fields:

- Block Count
- Chain (std::vector<Block>)

Methods:

• Constructor:

Blockchain::Blockchain(std::string debtor, std::string creditor, long long int moneyTransfer){
    // Create genesis block and add it to the chain
    utils::Data data;
    data.moneyTransfer  = moneyTransfer;
    data.debtor         = debtor;
    data.creditor       = creditor;
    long long unsigned initialIndex = 0;
    const char* zeroConstCharArr = "0";
    unsigned char* zeroHash = (unsigned char*)zeroConstCharArr;
    Block* genesisBlock = new Block(initialIndex, data, zeroHash);
    (this->chain).push_back(*genesisBlock);
    this->blockCount++;
}

• Get Latest Block : Gets the block added recently to the blockchain

Block Blockchain::getLatestBlock(){
    return this->chain[blockCount - 1];
}

• Add New Block

bool Blockchain::addNewBlock(Block newBlock){
    strcpy((char*)newBlock.prevHash, (char*)(this->getLatestBlock()).hash);
    newBlock.calculateHash();
    (this->chain).push_back(newBlock);
    this->blockCount++;
    return true;
}