void unpack_char(data_chunk& data, int carry)
{
for (auto it = data.rbegin(); it != data.rend(); it++)
{
carry += 58 * (*it);
*it = carry % 256;
carry /= 256;
}
BITCOIN_ASSERT(carry == 0);
}
void pack_value(data_chunk& indexes, int carry)
{
// Apply "b58 = b58 * 256 + ch".
for (auto it = indexes.rbegin(); it != indexes.rend(); ++it)
{
carry += 256 * (*it);
*it = carry % 58;
carry /= 58;
}
BITCOIN_ASSERT(carry == 0);
}
int main(int argc, char** argv)
{
if (argc != 5)
{
std::cerr << "Usage: pp_prove DOCUMENT CHUNKS BLOCK_HASH REVEAL"
<< std::endl;
return -1;
}
const fs::path doc_path = argv[1];
const std::string chunks_str = argv[2];
const std::string reveal_str = argv[4];
size_t chunks = 0, reveal = 0;
try
{
chunks = boost::lexical_cast<size_t>(chunks_str);
reveal = boost::lexical_cast<size_t>(reveal_str);
}
catch (const boost::bad_lexical_cast&)
{
std::cerr << "pp_start: bad CHUNKS or REVEAL provided." << std::endl;
return -1;
}
const data_chunk hash = decode_hex(argv[3]);
if (hash.empty() || hash.size() != hash_size)
{
std::cerr << "pp_prove: not a valid BLOCK_HASH." << std::endl;
return -1;
}
std::ifstream infile(doc_path.native(), std::ifstream::binary);
infile.seekg(0, std::ifstream::end);
size_t file_size = infile.tellg();
infile.seekg(0, std::ifstream::beg);
size_t chunk_size = file_size / chunks;
// AES works on blocks of 16 bytes. Round up to nearest multiple.
chunk_size += 16 - (chunk_size % 16);
BITCOIN_ASSERT(chunk_size % 16 == 0);
//std::cout << "Creating chunks of "
// << chunk_size << " bytes each." << std::endl;
ec_point_list all_pubkeys;
while (infile)
{
data_chunk buffer(chunk_size);
// Copy chunk to public chunk file.
char* data = reinterpret_cast<char*>(buffer.data());
infile.read(data, chunk_size);
// Create a seed.
BITCOIN_ASSERT(ec_secret_size == hash_size);
ec_secret secret = bitcoin_hash(buffer);
ec_point pubkey = secret_to_public_key(secret);
// Once we spend funds, we reveal the decryption pubkey.
all_pubkeys.push_back(pubkey);
}
// Beginning bytes of block hash are zero, so use end bytes.
std::seed_seq seq(hash.rbegin(), hash.rend());
index_list random_values(reveal);
seq.generate(random_values.begin(), random_values.end());
for (size_t value: random_values)
{
size_t index = value % all_pubkeys.size();
std::cout << (index + 1) << " " << all_pubkeys[index] << std::endl;
}
return 0;
}
