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block.cpp
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block.cpp
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#include "block.h"
#include <ctime>
#include <sstream>
#include <iomanip>
#include <openssl/evp.h>
#include <openssl/sha.h>
#include <iostream>
Block::Block(std::string previousHash, std::vector<Transaction> transactions)
: previousHash(previousHash), transactions(transactions), timestamp(std::time(nullptr)), nonce(0) {
hash = calculateHash();
}
std::string Block::calculateHash() const {
std::stringstream ss;
ss << previousHash << timestamp << nonce;
for (const auto& transaction : transactions) {
ss << transaction.toString();
}
return calculateHash(ss.str());
}
std::string Block::calculateHash(const std::string& data) {
unsigned char hash[SHA256_DIGEST_LENGTH];
EVP_MD_CTX* context = EVP_MD_CTX_new();
if (context == nullptr) {
throw std::runtime_error("Failed to create OpenSSL context");
}
if (EVP_DigestInit_ex(context, EVP_sha256(), nullptr) != 1 ||
EVP_DigestUpdate(context, data.c_str(), data.size()) != 1 ||
EVP_DigestFinal_ex(context, hash, nullptr) != 1) {
EVP_MD_CTX_free(context);
throw std::runtime_error("Failed to compute SHA-256 hash");
}
EVP_MD_CTX_free(context);
std::stringstream ss;
for (int i = 0; i < SHA256_DIGEST_LENGTH; ++i) {
ss << std::hex << std::setw(2) << std::setfill('0') << (int)hash[i];
}
return ss.str();
}
void Block::mineBlock(int difficulty) {
std::string target(difficulty, '0');
while (hash.substr(0, difficulty) != target) {
nonce++;
hash = calculateHash();
}
std::cout << "Block mined: " << hash << std::endl;
}