Blockchain

Blockchain implementation with C++20 and STL, all test were performed on Arch Linux.

Was done:

• Proof Of Work (Mining)
• Serialization
• Transactions
• Signing transactions
• More type for hashing
• Merkle trees
• P2P
• Consensus

Dependencies:

sudo pacman -S openssl
sudo pacman -S nlohmann-json

Build:

cd build
cmake ..
make
./run

Transaction signing example:

#include "../includes/blockchain.h"

// using namespace crypto::rsa;

int main()
{
    Blockchain chain;

    RSA* miner_private_key = crypto::rsa::generate_private_key();

    RSA* sender_private_key = crypto::rsa::generate_private_key();
    RSA* sender_public_key = crypto::rsa::generate_public_key(sender_private_key);

    RSA* receiver_private_key = crypto::rsa::generate_private_key();
    RSA* receiver_public_key = crypto::rsa::generate_public_key(receiver_private_key);

    Transaction test {"Sender", "Receiver", 250.5};

    test.sign(sender_private_key);
    
    if(test.verify(sender_public_key))
    {
        chain.create_transaction(test, sender_private_key);
        chain.mine_pending_transactions("wand", miner_private_key);

        std::cout << "Sender balance: " << chain.get_balance("Sender") << std::endl;
        std::cout << "Receiver balance: " << chain.get_balance("Receiver") << std::endl;
    }
    else
    {
        std::cerr << "Failed to sign transaction" << std::endl;
    }

    chain.mine_pending_transactions("wand", miner_private_key);

    std::cout << "Miner balance: " << chain.get_balance("wand") << std::endl;

    chain.get_blocks_data();

    std::cout << (chain.is_valid() ? "Chain are valid" : "Chain aren`t valid") << std::endl;

    return 0;
}

Output:

Sender balance: -250.5
Receiver balance: 250.5
Miner balance: 100
Index: 0
Nonce: 0
Hash: Genesis Block
Previous hash: Genesis Block
Timestamp: 1408
Transactions count: 0
Merkle root hash: 

Index: 1
Nonce: 852
Hash: 000a90e11be60a607bd75cbb0f4ce049493565edec85ec17896b80f1cd1be104
Previous hash: Genesis Block
Timestamp: 1346666548
Transactions count: 1
Merkle root hash: ce0356d39a072e660598e59bca7c511d2ca852b15c6e1ca4c0955e2f52382273

Index: 2
Nonce: 1640
Hash: 000d5f867849eeea0f4a8f175c13f2d95c26f134d0d4d43fff275feb3df009b8
Previous hash: 000a90e11be60a607bd75cbb0f4ce049493565edec85ec17896b80f1cd1be104
Timestamp: 1346666556
Transactions count: 1
Merkle root hash: 6f5430c287309c1ac847de0885835e7d5d32c1eff9f77084978896a6e538fc6a

Chain are valid