#NewsTrade The Bitcoin code is open source and available on GitHub. Below, I show you simplified snippets of the actual Bitcoin Core code (in C++), focused on key aspects of the algorithm:
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1. Generation of a block hash (double SHA-256)
In Bitcoin, each block is identified by a double SHA-256 hash (that is, SHA-256 is applied twice). This snippet represents that process:
#include
uint256 Hash(const std::vector& data) {
unsigned char hash1[SHA256_DIGEST_LENGTH];
SHA256(data.data(), data.size(), hash1);
unsigned char hash2[SHA256_DIGEST_LENGTH];
SHA256(hash1, SHA256_DIGEST_LENGTH, hash2);
return uint256(hash2); // final block hash
}
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2. Mining process: proof of work
This snippet represents a mining loop: it tests different nonce values until a valid hash is found with a certain number of leading zeros.
while (true) {
block.nNonce++;
uint256 hash = block.GetHash(); // applies double SHA-256 internally
if (hash < target) { // target is the current difficulty
// Valid block found!
break;
}
}
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3. Validation of a transaction
This checks if a transaction is valid (very simplified summary):
bool CheckTransaction(const CTransaction& tx) {
if (tx.vin.empty() || tx.vout.empty()) return false; // required inputs and outputs
// check that output values are not negative
for (const auto& out : tx.vout) {
if (out.nValue < 0) return false;
}
return true;
}
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