187 lines
8.5 KiB
C++
187 lines
8.5 KiB
C++
// Copyright (c) 2017-2018, The Monero Project
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other
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// materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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// used to endorse or promote products derived from this software without specific
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// prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include <unordered_set>
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#include "include_base_utils.h"
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#include "crypto/crypto.h"
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#include "ringct/rctOps.h"
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#include "cryptonote_basic/account.h"
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#include "cryptonote_basic/cryptonote_format_utils.h"
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#include "multisig.h"
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#undef MONERO_DEFAULT_LOG_CATEGORY
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#define MONERO_DEFAULT_LOG_CATEGORY "multisig"
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using namespace std;
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static const rct::key multisig_salt = { {'M', 'u', 'l', 't' , 'i', 's', 'i', 'g', 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } };
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namespace cryptonote
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{
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//-----------------------------------------------------------------
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crypto::secret_key get_multisig_blinded_secret_key(const crypto::secret_key &key)
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{
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rct::keyV data;
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data.reserve(2);
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data.push_back(rct::sk2rct(key));
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data.push_back(multisig_salt);
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crypto::secret_key result = rct::rct2sk(rct::hash_to_scalar(data));
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memwipe(&data[0], sizeof(rct::key));
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return result;
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}
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//-----------------------------------------------------------------
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void generate_multisig_N_N(const account_keys &keys, const std::vector<crypto::public_key> &spend_keys, std::vector<crypto::secret_key> &multisig_keys, rct::key &spend_skey, rct::key &spend_pkey)
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{
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// the multisig spend public key is the sum of all spend public keys
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multisig_keys.clear();
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const crypto::secret_key spend_secret_key = get_multisig_blinded_secret_key(keys.m_spend_secret_key);
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CHECK_AND_ASSERT_THROW_MES(crypto::secret_key_to_public_key(spend_secret_key, (crypto::public_key&)spend_pkey), "Failed to derive public key");
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for (const auto &k: spend_keys)
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rct::addKeys(spend_pkey, spend_pkey, rct::pk2rct(k));
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multisig_keys.push_back(spend_secret_key);
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spend_skey = rct::sk2rct(spend_secret_key);
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}
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//-----------------------------------------------------------------
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void generate_multisig_N1_N(const account_keys &keys, const std::vector<crypto::public_key> &spend_keys, std::vector<crypto::secret_key> &multisig_keys, rct::key &spend_skey, rct::key &spend_pkey)
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{
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multisig_keys.clear();
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spend_pkey = rct::identity();
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spend_skey = rct::zero();
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// create all our composite private keys
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crypto::secret_key blinded_skey = get_multisig_blinded_secret_key(keys.m_spend_secret_key);
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for (const auto &k: spend_keys)
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{
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rct::key sk = rct::scalarmultKey(rct::pk2rct(k), rct::sk2rct(blinded_skey));
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crypto::secret_key msk = get_multisig_blinded_secret_key(rct::rct2sk(sk));
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multisig_keys.push_back(msk);
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sc_add(spend_skey.bytes, spend_skey.bytes, (const unsigned char*)msk.data);
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}
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}
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//-----------------------------------------------------------------
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std::vector<crypto::public_key> generate_multisig_derivations(const account_keys &keys, const std::vector<crypto::public_key> &derivations)
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{
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std::vector<crypto::public_key> multisig_keys;
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crypto::secret_key blinded_skey = get_multisig_blinded_secret_key(keys.m_spend_secret_key);
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for (const auto &k: derivations)
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{
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rct::key d = rct::scalarmultKey(rct::pk2rct(k), rct::sk2rct(blinded_skey));
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multisig_keys.push_back(rct::rct2pk(d));
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}
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return multisig_keys;
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}
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//-----------------------------------------------------------------
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crypto::secret_key calculate_multisig_signer_key(const std::vector<crypto::secret_key>& multisig_keys)
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{
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rct::key secret_key = rct::zero();
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for (const auto &k: multisig_keys)
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{
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sc_add(secret_key.bytes, secret_key.bytes, (const unsigned char*)k.data);
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}
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return rct::rct2sk(secret_key);
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}
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//-----------------------------------------------------------------
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std::vector<crypto::secret_key> calculate_multisig_keys(const std::vector<crypto::public_key>& derivations)
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{
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std::vector<crypto::secret_key> multisig_keys;
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multisig_keys.reserve(derivations.size());
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for (const auto &k: derivations)
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{
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multisig_keys.emplace_back(get_multisig_blinded_secret_key(rct::rct2sk(rct::pk2rct(k))));
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}
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return multisig_keys;
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}
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//-----------------------------------------------------------------
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crypto::secret_key generate_multisig_view_secret_key(const crypto::secret_key &skey, const std::vector<crypto::secret_key> &skeys)
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{
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rct::key view_skey = rct::sk2rct(get_multisig_blinded_secret_key(skey));
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for (const auto &k: skeys)
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sc_add(view_skey.bytes, view_skey.bytes, rct::sk2rct(k).bytes);
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return rct::rct2sk(view_skey);
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}
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//-----------------------------------------------------------------
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crypto::public_key generate_multisig_M_N_spend_public_key(const std::vector<crypto::public_key> &pkeys)
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{
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rct::key spend_public_key = rct::identity();
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for (const auto &pk: pkeys)
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{
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rct::addKeys(spend_public_key, spend_public_key, rct::pk2rct(pk));
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}
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return rct::rct2pk(spend_public_key);
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}
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//-----------------------------------------------------------------
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bool generate_multisig_key_image(const account_keys &keys, size_t multisig_key_index, const crypto::public_key& out_key, crypto::key_image& ki)
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{
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if (multisig_key_index >= keys.m_multisig_keys.size())
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return false;
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crypto::generate_key_image(out_key, keys.m_multisig_keys[multisig_key_index], ki);
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return true;
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}
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//-----------------------------------------------------------------
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void generate_multisig_LR(const crypto::public_key pkey, const crypto::secret_key &k, crypto::public_key &L, crypto::public_key &R)
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{
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rct::scalarmultBase((rct::key&)L, rct::sk2rct(k));
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crypto::generate_key_image(pkey, k, (crypto::key_image&)R);
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}
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//-----------------------------------------------------------------
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bool generate_multisig_composite_key_image(const account_keys &keys, const std::unordered_map<crypto::public_key, subaddress_index>& subaddresses, const crypto::public_key& out_key, const crypto::public_key &tx_public_key, const std::vector<crypto::public_key>& additional_tx_public_keys, size_t real_output_index, const std::vector<crypto::key_image> &pkis, crypto::key_image &ki)
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{
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cryptonote::keypair in_ephemeral;
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if (!cryptonote::generate_key_image_helper(keys, subaddresses, out_key, tx_public_key, additional_tx_public_keys, real_output_index, in_ephemeral, ki, keys.get_device()))
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return false;
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std::unordered_set<crypto::key_image> used;
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for (size_t m = 0; m < keys.m_multisig_keys.size(); ++m)
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{
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crypto::key_image pki;
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bool r = cryptonote::generate_multisig_key_image(keys, m, out_key, pki);
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if (!r)
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return false;
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used.insert(pki);
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}
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for (const auto &pki: pkis)
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{
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if (used.find(pki) == used.end())
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{
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used.insert(pki);
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rct::addKeys((rct::key&)ki, rct::ki2rct(ki), rct::ki2rct(pki));
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}
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}
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return true;
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}
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//-----------------------------------------------------------------
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uint32_t multisig_rounds_required(uint32_t participants, uint32_t threshold)
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{
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CHECK_AND_ASSERT_THROW_MES(participants >= threshold, "participants must be greater or equal than threshold");
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return participants - threshold + 1;
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}
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}
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