add multisig core test and factor multisig building blocks

1 files changed, 152 insertions, 0 deletions

diff --git a/src/multisig/multisig.cpp b/src/multisig/multisig.cpp
new file mode 100644
index 000000000..0a9933b13
--- /dev/null
+++ b/src/multisig/multisig.cpp
@@ -0,0 +1,152 @@
+// Copyright (c) 2017, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <unordered_set>
+#include "include_base_utils.h"
+#include "crypto/crypto.h"
+#include "ringct/rctOps.h"
+#include "cryptonote_basic/account.h"
+#include "cryptonote_basic/cryptonote_format_utils.h"
+#include "multisig.h"
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "multisig"
+
+using namespace std;
+
+namespace cryptonote
+{
+  //-----------------------------------------------------------------
+  bool generate_key_image_helper_old(const account_keys& ack, const crypto::public_key& tx_public_key, size_t real_output_index, keypair& in_ephemeral, crypto::key_image& ki)
+  {
+    crypto::key_derivation recv_derivation = AUTO_VAL_INIT(recv_derivation);
+    bool r = crypto::generate_key_derivation(tx_public_key, ack.m_view_secret_key, recv_derivation);
+    CHECK_AND_ASSERT_MES(r, false, "key image helper: failed to generate_key_derivation(" << tx_public_key << ", " << ack.m_view_secret_key << ")");
+
+    r = crypto::derive_public_key(recv_derivation, real_output_index, ack.m_account_address.m_spend_public_key, in_ephemeral.pub);
+    CHECK_AND_ASSERT_MES(r, false, "key image helper: failed to derive_public_key(" << recv_derivation << ", " << real_output_index <<  ", " << ack.m_account_address.m_spend_public_key << ")");
+
+    crypto::derive_secret_key(recv_derivation, real_output_index, ack.m_spend_secret_key, in_ephemeral.sec);
+
+    crypto::generate_key_image(in_ephemeral.pub, in_ephemeral.sec, ki);
+    return true;
+  }
+  //-----------------------------------------------------------------
+  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)
+  {
+    // the multisig spend public key is the sum of all spend public keys
+    multisig_keys.clear();
+    spend_pkey = rct::pk2rct(keys.m_account_address.m_spend_public_key);
+    for (const auto &k: spend_keys)
+      rct::addKeys(spend_pkey, spend_pkey, rct::pk2rct(k));
+    multisig_keys.push_back(keys.m_spend_secret_key);
+    spend_skey = rct::sk2rct(keys.m_spend_secret_key);
+  }
+  //-----------------------------------------------------------------
+  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)
+  {
+    multisig_keys.clear();
+    spend_pkey = rct::identity();
+    spend_skey = rct::zero();
+
+    // create all our composite private keys
+    for (const auto &k: spend_keys)
+    {
+      rct::keyV data;
+      data.push_back(rct::scalarmultKey(rct::pk2rct(k), rct::sk2rct(keys.m_spend_secret_key)));
+      static const rct::key 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  } };
+      data.push_back(salt);
+      rct::key msk = rct::hash_to_scalar(data);
+      multisig_keys.push_back(rct::rct2sk(msk));
+      sc_add(spend_skey.bytes, spend_skey.bytes, msk.bytes);
+    }
+  }
+  //-----------------------------------------------------------------
+  crypto::secret_key generate_multisig_view_secret_key(const crypto::secret_key &skey, const std::vector<crypto::secret_key> &skeys)
+  {
+    crypto::hash hash;
+    crypto::cn_fast_hash(&skey, sizeof(crypto::hash), hash);
+    rct::key view_skey = rct::hash2rct(hash);
+    for (const auto &k: skeys)
+      sc_add(view_skey.bytes, view_skey.bytes, rct::sk2rct(k).bytes);
+    return rct::rct2sk(view_skey);
+  }
+  //-----------------------------------------------------------------
+  crypto::public_key generate_multisig_N1_N_spend_public_key(const std::vector<crypto::public_key> &pkeys)
+  {
+    rct::key spend_public_key = rct::identity();
+    for (const auto &pk: pkeys)
+    {
+      rct::addKeys(spend_public_key, spend_public_key, rct::pk2rct(pk));
+    }
+    return rct::rct2pk(spend_public_key);
+  }
+  //-----------------------------------------------------------------
+  bool generate_multisig_key_image(const account_keys &keys, const crypto::public_key& tx_public_key, size_t real_output_index, cryptonote::keypair& in_ephemeral, crypto::key_image& ki, size_t multisig_key_index)
+  {
+    if (multisig_key_index >= keys.m_multisig_keys.size())
+      return false;
+    if (!cryptonote::generate_key_image_helper_old(keys, tx_public_key, real_output_index, in_ephemeral, ki))
+      return false;
+    // we got the ephemeral keypair, but the key image isn't right as it's done as per our private spend key, which is multisig
+    crypto::generate_key_image(in_ephemeral.pub, keys.m_multisig_keys[multisig_key_index], ki);
+    return true;
+  }
+  //-----------------------------------------------------------------
+  void generate_multisig_LR(const crypto::public_key pkey, const crypto::secret_key &k, crypto::public_key &L, crypto::public_key &R)
+  {
+    rct::scalarmultBase((rct::key&)L, rct::sk2rct(k));
+    crypto::generate_key_image(pkey, k, (crypto::key_image&)R);
+  }
+  //-----------------------------------------------------------------
+  bool generate_multisig_composite_key_image(const account_keys &keys, const crypto::public_key &tx_public_key, size_t real_output_index, const std::vector<crypto::key_image> &pkis, crypto::key_image &ki)
+  {
+    cryptonote::keypair in_ephemeral;
+    if (!cryptonote::generate_key_image_helper_old(keys, tx_public_key, real_output_index, in_ephemeral, ki))
+      return false;
+    std::unordered_set<crypto::key_image> used;
+    for (size_t m = 0; m < keys.m_multisig_keys.size(); ++m)
+    {
+      crypto::key_image pki;
+      bool r = cryptonote::generate_multisig_key_image(keys, tx_public_key, real_output_index, in_ephemeral, pki, m);
+      if (!r)
+        return false;
+      used.insert(pki);
+    }
+    for (const auto &pki: pkis)
+    {
+      if (used.find(pki) == used.end())
+      {
+        used.insert(pki);
+        rct::addKeys((rct::key&)ki, rct::ki2rct(ki), rct::ki2rct(pki));
+      }
+    }
+    return true;
+  }
+  //-----------------------------------------------------------------
+}