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/*
* (C) 2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include "cli.h"
#if defined(BOTAN_HAS_THRESHOLD_SECRET_SHARING)
#include <botan/tss.h>
#include <botan/hex.h>
#include <botan/rng.h>
#include <fstream>
#endif
namespace Botan_CLI {
#if defined(BOTAN_HAS_THRESHOLD_SECRET_SHARING)
class TSS_Split final : public Command
{
public:
TSS_Split() : Command("tss_split M N input --id= --share-prefix=share --share-suffix=tss --hash=SHA-256") {}
std::string group() const override
{
return "tss";
}
std::string description() const override
{
return "Split a secret into parts";
}
void go() override
{
const std::string hash_algo = get_arg("hash");
const std::string input = get_arg("input");
const std::string id_str = get_arg("id");
const std::string share_prefix = get_arg("share-prefix");
const std::string share_suffix = get_arg("share-suffix");
const size_t N = get_arg_sz("N");
const size_t M = get_arg_sz("M");
if(M <= 1 || N <= 1 || M > N || N >= 255)
throw CLI_Usage_Error("Invalid N/M parameters for secret splitting");
Botan::secure_vector<uint8_t> secret = slurp_file_lvec(input);
if(secret.size() > 0xFFFF)
throw CLI_Usage_Error("Secret is too large for this TSS format");
std::vector<uint8_t> id = Botan::hex_decode(id_str);
if(id.empty())
{
id.resize(16);
rng().randomize(id.data(), id.size());
}
std::vector<Botan::RTSS_Share> shares =
Botan::RTSS_Share::split(static_cast<uint8_t>(M), static_cast<uint8_t>(N),
secret.data(), static_cast<uint16_t>(secret.size()),
id, hash_algo, rng());
for(size_t i = 0; i != shares.size(); ++i)
{
const std::string share_name = share_prefix + std::to_string(i + 1) + "." + share_suffix;
std::ofstream out(share_name.c_str());
if(!out)
throw CLI_Error("Failed to open output file " + share_name);
out.write(reinterpret_cast<const char*>(shares[i].data().data()), shares[i].data().size());
}
}
private:
Botan::secure_vector<uint8_t> slurp_file_lvec(const std::string& input_file)
{
Botan::secure_vector<uint8_t> buf;
auto insert_fn = [&](const uint8_t b[], size_t l)
{
buf.insert(buf.end(), b, b + l);
};
this->read_file(input_file, insert_fn, 4096);
return buf;
}
};
BOTAN_REGISTER_COMMAND("tss_split", TSS_Split);
class TSS_Recover final : public Command
{
public:
TSS_Recover() : Command("tss_recover *shares") {}
std::string group() const override
{
return "tss";
}
std::string description() const override
{
return "Recover a split secret";
}
void go() override
{
const std::vector<std::string> share_names = get_arg_list("shares");
if(share_names.empty())
{
output() << help_text() << "\n";
this->set_return_code(1);
return;
}
std::vector<Botan::RTSS_Share> shares;
for(std::string share_fsname : get_arg_list("shares"))
{
auto v = slurp_file(share_fsname);
shares.push_back(Botan::RTSS_Share(v.data(), v.size()));
}
Botan::secure_vector<uint8_t> rec = Botan::RTSS_Share::reconstruct(shares);
output().write(Botan::cast_uint8_ptr_to_char(rec.data()), rec.size());
}
};
BOTAN_REGISTER_COMMAND("tss_recover", TSS_Recover);
#endif
}