MMS (Multisig Messaging System): Initial version

1 files changed, 1445 insertions, 0 deletions

diff --git a/src/wallet/message_store.cpp b/src/wallet/message_store.cpp
new file mode 100644
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+++ b/src/wallet/message_store.cpp
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+// Copyright (c) 2018, 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 "message_store.h"
+#include <boost/archive/portable_binary_oarchive.hpp>
+#include <boost/archive/portable_binary_iarchive.hpp>
+#include <boost/format.hpp>
+#include <boost/algorithm/string.hpp>
+#include <fstream>
+#include <sstream>
+#include "file_io_utils.h"
+#include "storages/http_abstract_invoke.h"
+#include "wallet_errors.h"
+#include "serialization/binary_utils.h"
+#include "common/base58.h"
+#include "common/util.h"
+#include "string_tools.h"
+
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "wallet.mms"
+
+namespace mms
+{
+
+message_store::message_store()
+{
+  m_active = false;
+  m_auto_send = false;
+  m_next_message_id = 1;
+  m_num_authorized_signers = 0;
+  m_num_required_signers = 0;
+  m_nettype = cryptonote::network_type::UNDEFINED;
+  m_run = true;
+}
+
+namespace
+{
+  // MMS options handling mirrors what "wallet2" is doing for its options, on-demand init and all
+  // It's not very clean to initialize Bitmessage-specific options here, but going one level further
+  // down still into "message_transporter" for that is a little bit too much
+  struct options
+  {
+    const command_line::arg_descriptor<std::string> bitmessage_address = {"bitmessage-address", mms::message_store::tr("Use PyBitmessage instance at URL <arg>"), "http://localhost:8442/"};
+    const command_line::arg_descriptor<std::string> bitmessage_login = {"bitmessage-login", mms::message_store::tr("Specify <arg> as username:password for PyBitmessage API"), "username:password"};
+  };
+}
+
+void message_store::init_options(boost::program_options::options_description& desc_params)
+{
+  const options opts{};
+  command_line::add_arg(desc_params, opts.bitmessage_address);
+  command_line::add_arg(desc_params, opts.bitmessage_login);
+}
+
+void message_store::init(const multisig_wallet_state &state, const std::string &own_label,
+                         const std::string &own_transport_address, uint32_t num_authorized_signers, uint32_t num_required_signers)
+{
+  m_num_authorized_signers = num_authorized_signers;
+  m_num_required_signers = num_required_signers;
+  m_signers.clear();
+  m_messages.clear();
+  m_next_message_id = 1;
+
+  // The vector "m_signers" gets here once the required number of elements, one for each authorized signer,
+  // and is never changed again. The rest of the code relies on "size(m_signers) == m_num_authorized_signers"
+  // without further checks.
+  authorized_signer signer;
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    signer.me = signer.index == 0;    // Strict convention: The very first signer is fixed as / must be "me"
+    m_signers.push_back(signer);
+    signer.index++;
+  }
+
+  set_signer(state, 0, own_label, own_transport_address, state.address);
+
+  m_nettype = state.nettype;
+  set_active(true);
+  m_filename = state.mms_file;
+  save(state);
+}
+
+void message_store::set_options(const boost::program_options::variables_map& vm)
+{
+  const options opts{};
+  std::string bitmessage_address = command_line::get_arg(vm, opts.bitmessage_address);
+  epee::wipeable_string bitmessage_login = command_line::get_arg(vm, opts.bitmessage_login);
+  set_options(bitmessage_address, bitmessage_login);
+}
+
+void message_store::set_options(const std::string &bitmessage_address, const epee::wipeable_string &bitmessage_login)
+{
+  m_transporter.set_options(bitmessage_address, bitmessage_login);
+}
+
+void message_store::set_signer(const multisig_wallet_state &state,
+                               uint32_t index,
+                               const boost::optional<std::string> &label,
+                               const boost::optional<std::string> &transport_address,
+                               const boost::optional<cryptonote::account_public_address> monero_address)
+{
+  THROW_WALLET_EXCEPTION_IF(index >= m_num_authorized_signers, tools::error::wallet_internal_error, "Invalid signer index " + index);
+  authorized_signer &m = m_signers[index];
+  if (label)
+  {
+    m.label = label.get();
+  }
+  if (transport_address)
+  {
+    m.transport_address = transport_address.get();
+  }
+  if (monero_address)
+  {
+    m.monero_address_known = true;
+    m.monero_address = monero_address.get();
+  }
+  // Save to minimize the chance to loose that info (at least while in beta)
+  save(state);
+}
+
+const authorized_signer &message_store::get_signer(uint32_t index) const
+{
+  THROW_WALLET_EXCEPTION_IF(index >= m_num_authorized_signers, tools::error::wallet_internal_error, "Invalid signer index " + index);
+  return m_signers[index];
+}
+
+bool message_store::signer_config_complete() const
+{
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = m_signers[i];
+    if (m.label.empty() || m.transport_address.empty() || !m.monero_address_known)
+    {
+      return false;
+    }
+  }
+  return true;
+}
+
+// Check if all signers have a label set (as it's a requirement for starting auto-config
+// by the "manager")
+bool message_store::signer_labels_complete() const
+{
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = m_signers[i];
+    if (m.label.empty())
+    {
+      return false;
+    }
+  }
+  return true;
+}
+
+void message_store::get_signer_config(std::string &signer_config)
+{
+  std::stringstream oss;
+  boost::archive::portable_binary_oarchive ar(oss);
+  ar << m_signers;
+  signer_config = oss.str();
+}
+
+void message_store::unpack_signer_config(const multisig_wallet_state &state, const std::string &signer_config,
+                                         std::vector<authorized_signer> &signers)
+{
+  try
+  {
+    std::stringstream iss;
+    iss << signer_config;
+    boost::archive::portable_binary_iarchive ar(iss);
+    ar >> signers;
+  }
+  catch (...)
+  {
+    THROW_WALLET_EXCEPTION_IF(true, tools::error::wallet_internal_error, "Invalid structure of signer config");
+  }
+  uint32_t num_signers = (uint32_t)signers.size();
+  THROW_WALLET_EXCEPTION_IF(num_signers != m_num_authorized_signers, tools::error::wallet_internal_error, "Wrong number of signers in config: " + num_signers);
+}
+
+void message_store::process_signer_config(const multisig_wallet_state &state, const std::string &signer_config)
+{
+  // The signers in "signer_config" and the resident wallet signers are matched not by label, but
+  // by Monero address, and ALL labels will be set from "signer_config", even the "me" label.
+  // In the auto-config process as implemented now the auto-config manager is responsible for defining
+  // the labels, and right at the end of the process ALL wallets use the SAME labels. The idea behind this
+  // is preventing problems like duplicate labels and confusion (Bob choosing a label "IamAliceHonest").
+  // (Of course signers are free to re-define any labels they don't like AFTER auto-config.)
+  //
+  // Usually this method will be called with only the "me" signer defined in the wallet, and may
+  // produce unexpected behaviour if that wallet contains additional signers that have nothing to do with
+  // those arriving in "signer_config".
+  std::vector<authorized_signer> signers;
+  unpack_signer_config(state, signer_config, signers);
+  
+  uint32_t new_index = 1;
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = signers[i];
+    uint32_t index;
+    uint32_t take_index;
+    bool found = get_signer_index_by_monero_address(m.monero_address, index);
+    if (found)
+    {
+      // Redefine existing (probably "me", under usual circumstances)
+      take_index = index;
+    }
+    else
+    {
+      // Add new; neglect that we may erroneously overwrite already defined signers
+      // (but protect "me")
+      take_index = new_index;
+      if ((new_index + 1) < m_num_authorized_signers)
+      {
+        new_index++;
+      }
+    }
+    authorized_signer &modify = m_signers[take_index];
+    modify.label = m.label;  // ALWAYS set label, see comments above
+    if (!modify.me)
+    {
+      modify.transport_address = m.transport_address;
+      modify.monero_address_known = m.monero_address_known;
+      if (m.monero_address_known)
+      {
+        modify.monero_address = m.monero_address;
+      }
+    }
+  }
+  save(state);
+}
+
+void message_store::start_auto_config(const multisig_wallet_state &state)
+{
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    authorized_signer &m = m_signers[i];
+    if (!m.me)
+    {
+      setup_signer_for_auto_config(i, create_auto_config_token(), true);
+    }
+    m.auto_config_running = true;
+  }
+  save(state);
+}
+
+// Check auto-config token string and convert to standardized form;
+// Try to make it as foolproof as possible, with built-in tolerance to make up for
+// errors in transmission that still leave the token recognizable.
+bool message_store::check_auto_config_token(const std::string &raw_token,
+                                            std::string &adjusted_token) const
+{
+  std::string prefix(AUTO_CONFIG_TOKEN_PREFIX);
+  uint32_t num_hex_digits = (AUTO_CONFIG_TOKEN_BYTES + 1) * 2;
+  uint32_t full_length = num_hex_digits + prefix.length();
+  uint32_t raw_length = raw_token.length();
+  std::string hex_digits;
+
+  if (raw_length == full_length)
+  {
+    // Prefix must be there; accept it in any casing
+    std::string raw_prefix(raw_token.substr(0, 3));
+    boost::algorithm::to_lower(raw_prefix);
+    if (raw_prefix != prefix)
+    {
+      return false;
+    }
+    hex_digits = raw_token.substr(3);
+  }
+  else if (raw_length == num_hex_digits)
+  {
+    // Accept the token without the prefix if it's otherwise ok
+    hex_digits = raw_token;
+  }
+  else
+  {
+    return false;
+  }
+
+  // Convert to strict lowercase and correct any common misspellings
+  boost::algorithm::to_lower(hex_digits);
+  std::replace(hex_digits.begin(), hex_digits.end(), 'o', '0');
+  std::replace(hex_digits.begin(), hex_digits.end(), 'i', '1');
+  std::replace(hex_digits.begin(), hex_digits.end(), 'l', '1');
+
+  // Now it must be correct hex with correct checksum, no further tolerance possible
+  std::string token_bytes;
+  if (!epee::string_tools::parse_hexstr_to_binbuff(hex_digits, token_bytes))
+  {
+    return false;
+  }
+  const crypto::hash &hash = crypto::cn_fast_hash(token_bytes.data(), token_bytes.size() - 1);
+  if (token_bytes[AUTO_CONFIG_TOKEN_BYTES] != hash.data[0])
+  {
+    return false;
+  }
+  adjusted_token = prefix + hex_digits;
+  return true;
+}
+
+// Create a new auto-config token with prefix, random 8-hex digits plus 2 checksum digits
+std::string message_store::create_auto_config_token()
+{
+  unsigned char random[AUTO_CONFIG_TOKEN_BYTES];
+  crypto::rand(AUTO_CONFIG_TOKEN_BYTES, random);
+  std::string token_bytes;
+  token_bytes.append((char *)random, AUTO_CONFIG_TOKEN_BYTES);
+
+  // Add a checksum because technically ANY four bytes are a valid token, and without a checksum we would send
+  // auto-config messages "to nowhere" after the slightest typo without knowing it
+  const crypto::hash &hash = crypto::cn_fast_hash(token_bytes.data(), token_bytes.size());
+  token_bytes += hash.data[0];
+  std::string prefix(AUTO_CONFIG_TOKEN_PREFIX);
+  return prefix + epee::string_tools::buff_to_hex_nodelimer(token_bytes);
+}
+
+// Add a message for sending "me" address data to the auto-config transport address
+// that can be derived from the token and activate auto-config
+size_t message_store::add_auto_config_data_message(const multisig_wallet_state &state,
+                                                   const std::string &auto_config_token)
+{
+  authorized_signer &me = m_signers[0];
+  me.auto_config_token = auto_config_token;
+  setup_signer_for_auto_config(0, auto_config_token, false);
+  me.auto_config_running = true;
+
+  auto_config_data data;
+  data.label = me.label;
+  data.transport_address = me.transport_address;
+  data.monero_address = me.monero_address;
+
+  std::stringstream oss;
+  boost::archive::portable_binary_oarchive ar(oss);
+  ar << data;
+
+  return add_message(state, 0, message_type::auto_config_data, message_direction::out, oss.str());
+}
+
+// Process a single message with auto-config data, destined for "message.signer_index"
+void message_store::process_auto_config_data_message(uint32_t id)
+{
+  // "auto_config_data" contains the label that the auto-config data sender uses for "me", but that's
+  // more for completeness' sake, and right now it's not used. In general, the auto-config manager
+  // decides/defines the labels, and right after completing auto-config ALL wallets use the SAME labels.
+
+  const message &m = get_message_ref_by_id(id);
+
+  auto_config_data data;
+  try
+  {
+    std::stringstream iss;
+    iss << m.content;
+    boost::archive::portable_binary_iarchive ar(iss);
+    ar >> data;
+  }
+  catch (...)
+  {
+    THROW_WALLET_EXCEPTION_IF(true, tools::error::wallet_internal_error, "Invalid structure of auto config data");
+  }
+
+  authorized_signer &signer = m_signers[m.signer_index];
+  // "signer.label" does NOT change, see comment above
+  signer.transport_address = data.transport_address;
+  signer.monero_address_known = true;
+  signer.monero_address = data.monero_address;
+  signer.auto_config_running = false;
+}
+
+void message_store::stop_auto_config()
+{
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    authorized_signer &m = m_signers[i];
+    if (!m.me && !m.auto_config_transport_address.empty())
+    {
+      // Try to delete those "unused API" addresses in PyBitmessage, especially since
+      // it seems it's not possible to delete them interactively, only to "disable" them
+      m_transporter.delete_transport_address(m.auto_config_transport_address);
+    }
+    m.auto_config_token.clear();
+    m.auto_config_public_key = crypto::null_pkey;
+    m.auto_config_secret_key = crypto::null_skey;
+    m.auto_config_transport_address.clear();
+    m.auto_config_running = false;
+  }  
+}
+
+void message_store::setup_signer_for_auto_config(uint32_t index, const std::string token, bool receiving)
+{
+  // It may be a little strange to hash the textual hex digits of the auto config token into
+  // 32 bytes and turn that into a Monero public/secret key pair, instead of doing something
+  // much less complicated like directly using the underlying random 40 bits as key for a
+  // symmetric cipher, but everything is there already for encrypting and decrypting messages
+  // with such key pairs, and furthermore it would be trivial to use tokens with a different
+  // number of bytes.
+  //
+  // In the wallet of the auto-config manager each signer except "me" gets set its own
+  // auto-config parameters. In the wallet of somebody using the token to send auto-config
+  // data the auto-config parameters are stored in the "me" signer and taken from there
+  // to send that data.
+  THROW_WALLET_EXCEPTION_IF(index >= m_num_authorized_signers, tools::error::wallet_internal_error, "Invalid signer index " + index);
+  authorized_signer &m = m_signers[index];
+  m.auto_config_token = token;
+  crypto::hash_to_scalar(token.data(), token.size(), m.auto_config_secret_key);
+  crypto::secret_key_to_public_key(m.auto_config_secret_key, m.auto_config_public_key);
+  if (receiving)
+  {
+    m.auto_config_transport_address = m_transporter.derive_and_receive_transport_address(m.auto_config_token);
+  }
+  else
+  {
+    m.auto_config_transport_address = m_transporter.derive_transport_address(m.auto_config_token);
+  }
+}
+
+bool message_store::get_signer_index_by_monero_address(const cryptonote::account_public_address &monero_address, uint32_t &index) const
+{
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = m_signers[i];
+    if (m.monero_address == monero_address)
+    {
+      index = m.index;
+      return true;
+    }
+  }
+  MWARNING("No authorized signer with Monero address " << account_address_to_string(monero_address));
+  return false;
+}
+
+bool message_store::get_signer_index_by_label(const std::string label, uint32_t &index) const
+{
+  for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = m_signers[i];
+    if (m.label == label)
+    {
+      index = m.index;
+      return true;
+    }
+  }
+  MWARNING("No authorized signer with label " << label);
+  return false;
+}
+
+void message_store::process_wallet_created_data(const multisig_wallet_state &state, message_type type, const std::string &content)
+{
+  switch(type)
+  {
+  case message_type::key_set:
+    // Result of a "prepare_multisig" command in the wallet
+    // Send the key set to all other signers
+  case message_type::additional_key_set:
+    // Result of a "make_multisig" command or a "exchange_multisig_keys" in the wallet in case of M/N multisig
+    // Send the additional key set to all other signers
+  case message_type::multisig_sync_data:
+    // Result of a "export_multisig_info" command in the wallet
+    // Send the sync data to all other signers
+    for (uint32_t i = 1; i < m_num_authorized_signers; ++i)
+    {
+      add_message(state, i, type, message_direction::out, content);
+    }
+    break;
+
+  case message_type::partially_signed_tx:
+    // Result of a "transfer" command in the wallet, or a "sign_multisig" command
+    // that did not yet result in the minimum number of signatures required
+    // Create a message "from me to me" as a container for the tx data
+    if (m_num_required_signers == 1)
+    {
+      // Probably rare, but possible: The 1 signature is already enough, correct the type
+      // Easier to correct here than asking all callers to detect this rare special case
+      type = message_type::fully_signed_tx;
+    }
+    add_message(state, 0, type, message_direction::in, content);
+    break;
+
+  case message_type::fully_signed_tx:
+    add_message(state, 0, type, message_direction::in, content);
+    break;
+
+  default:
+    THROW_WALLET_EXCEPTION(tools::error::wallet_internal_error, "Illegal message type " + (uint32_t)type);
+    break;
+  }
+}
+
+size_t message_store::add_message(const multisig_wallet_state &state,
+                                  uint32_t signer_index, message_type type, message_direction direction,
+                                  const std::string &content)
+{
+  message m;
+  m.id = m_next_message_id++;
+  m.type = type;
+  m.direction = direction;
+  m.content = content;
+  m.created = (uint64_t)time(NULL);
+  m.modified = m.created;
+  m.sent = 0;
+  m.signer_index = signer_index;
+  if (direction == message_direction::out)
+  {
+    m.state = message_state::ready_to_send;
+  }
+  else
+  {
+    m.state = message_state::waiting;
+  };
+  m.wallet_height = (uint32_t)state.num_transfer_details;
+  if (m.type == message_type::additional_key_set)
+  {
+    m.round = state.multisig_rounds_passed;
+  }
+  else
+  {
+    m.round = 0;
+  }
+  m.signature_count = 0;  // Future expansion for signature counting when signing txs
+  m.hash = crypto::null_hash;
+  m_messages.push_back(m);
+
+  // Save for every new message right away (at least while in beta)
+  save(state);
+
+  MINFO(boost::format("Added %s message %s for signer %s of type %s")
+          % message_direction_to_string(direction) % m.id % signer_index % message_type_to_string(type));
+  return m_messages.size() - 1;
+}
+
+// Get the index of the message with id "id", return false if not found
+bool message_store::get_message_index_by_id(uint32_t id, size_t &index) const
+{
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    if (m_messages[i].id == id)
+    {
+      index = i;
+      return true;
+    }
+  }
+  MWARNING("No message found with an id of " << id);
+  return false;
+}
+
+// Get the index of the message with id "id" that must exist
+size_t message_store::get_message_index_by_id(uint32_t id) const
+{
+  size_t index;
+  bool found = get_message_index_by_id(id, index);
+  THROW_WALLET_EXCEPTION_IF(!found, tools::error::wallet_internal_error, "Invalid message id " + id);
+  return index;
+}
+
+// Get the modifiable message with id "id" that must exist; private/internal use!
+message& message_store::get_message_ref_by_id(uint32_t id)
+{
+  return m_messages[get_message_index_by_id(id)];
+}
+
+// Get the message with id "id", return false if not found
+// This version of the method allows to check whether id is valid without triggering an error
+bool message_store::get_message_by_id(uint32_t id, message &m) const
+{
+  size_t index;
+  bool found = get_message_index_by_id(id, index);
+  if (found)
+  {
+    m = m_messages[index];
+  }
+  return found;
+}
+
+// Get the message with id "id" that must exist
+message message_store::get_message_by_id(uint32_t id) const
+{
+  message m;
+  bool found = get_message_by_id(id, m);
+  THROW_WALLET_EXCEPTION_IF(!found, tools::error::wallet_internal_error, "Invalid message id " + id);
+  return m;
+}
+
+bool message_store::any_message_of_type(message_type type, message_direction direction) const
+{
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    if ((m_messages[i].type == type) && (m_messages[i].direction == direction))
+    {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool message_store::any_message_with_hash(const crypto::hash &hash) const
+{
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    if (m_messages[i].hash == hash)
+    {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Count the ids in the vector that are set i.e. not 0, while ignoring index 0
+// Mostly used to check whether we have a message for each authorized signer except me,
+// with the signer index used as index into 'ids'; the element at index 0, for me,
+// is ignored, to make constant subtractions of 1 for indices when filling the
+// vector unnecessary
+size_t message_store::get_other_signers_id_count(const std::vector<uint32_t> &ids) const
+{
+  size_t count = 0;
+  for (size_t i = 1 /* and not 0 */; i < ids.size(); ++i)
+  {
+    if (ids[i] != 0)
+    {
+      count++;
+    }
+  }
+  return count;
+}
+
+// Is in every element of vector 'ids' (except at index 0) a message id i.e. not 0?
+bool message_store::message_ids_complete(const std::vector<uint32_t> &ids) const
+{
+  return get_other_signers_id_count(ids) == (ids.size() - 1);
+}
+
+void message_store::delete_message(uint32_t id)
+{
+  delete_transport_message(id);
+  size_t index = get_message_index_by_id(id);
+  m_messages.erase(m_messages.begin() + index);
+}
+
+void message_store::delete_all_messages()
+{
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    delete_transport_message(m_messages[i].id);
+  }
+  m_messages.clear();
+}
+
+// Make a message text, which is "attacker controlled data", reasonably safe to display
+// This is mostly geared towards the safe display of notes sent by "mms note" with a "mms show" command
+void message_store::get_sanitized_message_text(const message &m, std::string &sanitized_text) const
+{
+  sanitized_text.clear();
+
+  // Restrict the size to fend of DOS-style attacks with heaps of data
+  size_t length = std::min(m.content.length(), (size_t)1000);
+
+  for (size_t i = 0; i < length; ++i)
+  {
+    char c = m.content[i];
+    if ((int)c < 32)
+    {
+      // Strip out any controls, especially ESC for getting rid of potentially dangerous
+      // ANSI escape sequences that a console window might interpret
+      c = ' ';
+    }
+    else if ((c == '<') || (c == '>'))
+    {
+      // Make XML or HTML impossible that e.g. might contain scripts that Qt might execute
+      // when displayed in the GUI wallet
+      c = ' ';
+    }
+    sanitized_text += c;
+  }
+}
+
+void message_store::write_to_file(const multisig_wallet_state &state, const std::string &filename)
+{
+  std::stringstream oss;
+  boost::archive::portable_binary_oarchive ar(oss);
+  ar << *this;
+  std::string buf = oss.str();
+
+  crypto::chacha_key key;
+  crypto::generate_chacha_key(&state.view_secret_key, sizeof(crypto::secret_key), key, 1);
+
+  file_data write_file_data = boost::value_initialized<file_data>();
+  write_file_data.magic_string = "MMS";
+  write_file_data.file_version = 0;
+  write_file_data.iv = crypto::rand<crypto::chacha_iv>();
+  std::string encrypted_data;
+  encrypted_data.resize(buf.size());
+  crypto::chacha20(buf.data(), buf.size(), key, write_file_data.iv, &encrypted_data[0]);
+  write_file_data.encrypted_data = encrypted_data;
+
+  std::stringstream file_oss;
+  boost::archive::portable_binary_oarchive file_ar(file_oss);
+  file_ar << write_file_data;
+
+  bool success = epee::file_io_utils::save_string_to_file(filename, file_oss.str());
+  THROW_WALLET_EXCEPTION_IF(!success, tools::error::file_save_error, filename);
+}
+
+void message_store::read_from_file(const multisig_wallet_state &state, const std::string &filename)
+{
+  boost::system::error_code ignored_ec;
+  bool file_exists = boost::filesystem::exists(filename, ignored_ec);
+  if (!file_exists)
+  {
+    // Simply do nothing if the file is not there; allows e.g. easy recovery
+    // from problems with the MMS by deleting the file
+    MERROR("No message store file found: " << filename);
+    return;
+  }
+
+  std::string buf;
+  bool success = epee::file_io_utils::load_file_to_string(filename, buf);
+  THROW_WALLET_EXCEPTION_IF(!success, tools::error::file_read_error, filename);
+
+  file_data read_file_data;
+  try
+  {
+    std::stringstream iss;
+    iss << buf;
+    boost::archive::portable_binary_iarchive ar(iss);
+    ar >> read_file_data;
+  }
+  catch (const std::exception &e)
+  {
+    MERROR("MMS file " << filename << " has bad structure <iv,encrypted_data>: " << e.what());
+    THROW_WALLET_EXCEPTION_IF(true, tools::error::file_read_error, filename);
+  }
+
+  crypto::chacha_key key;
+  crypto::generate_chacha_key(&state.view_secret_key, sizeof(crypto::secret_key), key, 1);
+  std::string decrypted_data;
+  decrypted_data.resize(read_file_data.encrypted_data.size());
+  crypto::chacha20(read_file_data.encrypted_data.data(), read_file_data.encrypted_data.size(), key, read_file_data.iv, &decrypted_data[0]);
+
+  try
+  {
+    std::stringstream iss;
+    iss << decrypted_data;
+    boost::archive::portable_binary_iarchive ar(iss);
+    ar >> *this;
+  }
+  catch (const std::exception &e)
+  {
+    MERROR("MMS file " << filename << " has bad structure: " << e.what());
+    THROW_WALLET_EXCEPTION_IF(true, tools::error::file_read_error, filename);
+  }
+
+  m_filename = filename;
+}
+
+// Save to the same file this message store was loaded from
+// Called after changes deemed "important", to make it less probable to lose messages in case of
+// a crash; a better and long-term solution would of course be to use LMDB ...
+void message_store::save(const multisig_wallet_state &state)
+{
+  if (!m_filename.empty())
+  {
+    write_to_file(state, m_filename);
+  }
+}
+
+bool message_store::get_processable_messages(const multisig_wallet_state &state,
+                                             bool force_sync, std::vector<processing_data> &data_list, std::string &wait_reason)
+{
+  uint32_t wallet_height = (uint32_t)state.num_transfer_details;
+  data_list.clear();
+  wait_reason.clear();
+  // In all scans over all messages looking for complete sets (1 message for each signer),
+  // if there are duplicates, the OLDEST of them is taken. This may not play a role with
+  // any of the current message types, but may with future ones, and it's probably a good
+  // idea to have a clear and somewhat defensive strategy.
+
+  std::vector<uint32_t> auto_config_messages(m_num_authorized_signers, 0);
+  bool any_auto_config = false;
+
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    message &m = m_messages[i];
+    if ((m.type == message_type::auto_config_data) && (m.state == message_state::waiting))
+    {
+      if (auto_config_messages[m.signer_index] == 0)
+      {
+        auto_config_messages[m.signer_index] = m.id;
+        any_auto_config = true;
+      }
+      // else duplicate auto config data, ignore
+    }
+  }
+
+  if (any_auto_config)
+  {
+    bool auto_config_complete = message_ids_complete(auto_config_messages);
+    if (auto_config_complete)
+    {
+      processing_data data;
+      data.processing = message_processing::process_auto_config_data;
+      data.message_ids = auto_config_messages;
+      data.message_ids.erase(data.message_ids.begin());
+      data_list.push_back(data);
+      return true;
+    }
+    else
+    {
+      wait_reason = tr("Auto-config cannot proceed because auto config data from other signers is not complete");
+      return false;
+      // With ANY auto config data present but not complete refuse to check for any
+      // other processing. Manually delete those messages to abort such an auto config
+      // phase if needed.
+    }
+  }
+
+  // Any signer config that arrived will be processed right away, regardless of other things that may wait
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    message &m = m_messages[i];
+    if ((m.type == message_type::signer_config) && (m.state == message_state::waiting))
+    {
+      processing_data data;
+      data.processing = message_processing::process_signer_config;
+      data.message_ids.push_back(m.id);
+      data_list.push_back(data);
+      return true;
+    }
+  }
+
+  // ALL of the following processings depend on the signer info being complete
+  if (!signer_config_complete())
+  {
+    wait_reason = tr("The signer config is not complete.");
+    return false;
+  }
+
+  if (!state.multisig)
+  {
+    
+    if (!any_message_of_type(message_type::key_set, message_direction::out))
+    {
+      // With the own key set not yet ready we must do "prepare_multisig" first;
+      // Key sets from other signers may be here already, but if we process them now
+      // the wallet will go multisig too early: we can't produce our own key set any more!
+      processing_data data;
+      data.processing = message_processing::prepare_multisig;
+      data_list.push_back(data);
+      return true;
+    }
+
+    // Ids of key set messages per signer index, to check completeness
+    // Naturally, does not care about the order of the messages and is trivial to secure against
+    // key sets that were received more than once
+    // With full M/N multisig now possible consider only key sets of the right round, i.e.
+    // with not yet multisig the only possible round 0
+    std::vector<uint32_t> key_set_messages(m_num_authorized_signers, 0);
+
+    for (size_t i = 0; i < m_messages.size(); ++i)
+    {
+      message &m = m_messages[i];
+      if ((m.type == message_type::key_set) && (m.state == message_state::waiting)
+          && (m.round == 0))
+      {
+        if (key_set_messages[m.signer_index] == 0)
+        {
+          key_set_messages[m.signer_index] = m.id;
+        }
+        // else duplicate key set, ignore
+      }
+    }
+
+    bool key_sets_complete = message_ids_complete(key_set_messages);
+    if (key_sets_complete)
+    {
+      // Nothing else can be ready to process earlier than this, ignore everything else and give back
+      processing_data data;
+      data.processing = message_processing::make_multisig;
+      data.message_ids = key_set_messages;
+      data.message_ids.erase(data.message_ids.begin());
+      data_list.push_back(data);
+      return true;
+    }
+    else
+    {
+      wait_reason = tr("Wallet can't go multisig because key sets from other signers are missing or not complete.");
+      return false;
+    }
+  }
+
+  if (state.multisig && !state.multisig_is_ready)
+  {
+    // In the case of M/N multisig the call 'wallet2::multisig' returns already true
+    // after "make_multisig" but with calls to "exchange_multisig_keys" still needed, and
+    // sets the parameter 'ready' to false to document this particular "in-between" state.
+    // So what may be possible here, with all necessary messages present, is a call to
+    // "exchange_multisig_keys".
+    // Consider only messages belonging to the next round to do, which has the number
+    // "state.multisig_rounds_passed".
+    std::vector<uint32_t> additional_key_set_messages(m_num_authorized_signers, 0);
+
+    for (size_t i = 0; i < m_messages.size(); ++i)
+    {
+      message &m = m_messages[i];
+      if ((m.type == message_type::additional_key_set) && (m.state == message_state::waiting)
+         && (m.round == state.multisig_rounds_passed))
+      {
+        if (additional_key_set_messages[m.signer_index] == 0)
+        {
+          additional_key_set_messages[m.signer_index] = m.id;
+        }
+        // else duplicate key set, ignore
+      }
+    }
+
+    bool key_sets_complete = message_ids_complete(additional_key_set_messages);
+    if (key_sets_complete)
+    {
+      processing_data data;
+      data.processing = message_processing::exchange_multisig_keys;
+      data.message_ids = additional_key_set_messages;
+      data.message_ids.erase(data.message_ids.begin());
+      data_list.push_back(data);
+      return true;
+    }
+    else
+    {
+      wait_reason = tr("Wallet can't start another key exchange round because key sets from other signers are missing or not complete.");
+      return false;
+    }
+  }
+
+  // Properly exchanging multisig sync data is easiest and most transparent
+  // for the user if a wallet sends its own data first and processes any received
+  // sync data afterwards so that's the order that the MMS enforces here.
+  // (Technically, it seems to work also the other way round.)
+  //
+  // To check whether a NEW round of syncing is necessary the MMS works with a
+  // "wallet state": new state means new syncing needed.
+  //
+  // The MMS monitors the "wallet state" by recording "wallet heights" as
+  // numbers of transfers present in a wallet at the time of message creation. While
+  // not watertight, this quite simple scheme should already suffice to trigger
+  // and orchestrate a sensible exchange of sync data.
+  if (state.has_multisig_partial_key_images || force_sync)
+  {
+    // Sync is necessary and not yet completed: Processing of transactions
+    // will only be possible again once properly synced
+    // Check first whether we generated already OUR sync info; take note of
+    // any processable sync info from other signers on the way in case we need it
+    bool own_sync_data_created = false;
+    std::vector<uint32_t> sync_messages(m_num_authorized_signers, 0);
+    for (size_t i = 0; i < m_messages.size(); ++i)
+    {
+      message &m = m_messages[i];
+      if ((m.type == message_type::multisig_sync_data) && (force_sync || (m.wallet_height == wallet_height)))
+      // It's data for the same "round" of syncing, on the same "wallet height", therefore relevant
+      // With "force_sync" take ANY waiting sync data, maybe it will work out
+      {
+        if (m.direction == message_direction::out)
+        {
+          own_sync_data_created = true;
+          // Ignore whether sent already or not, and assume as complete if several other signers there
+        }
+        else if ((m.direction == message_direction::in) && (m.state == message_state::waiting))
+        {
+          if (sync_messages[m.signer_index] == 0)
+          {
+            sync_messages[m.signer_index] = m.id;
+          }
+          // else duplicate sync message, ignore
+        }
+      }
+    }
+    if (!own_sync_data_created)
+    {
+      // As explained above, creating sync data BEFORE processing such data from
+      // other signers reliably works, so insist on that here
+      processing_data data;
+      data.processing = message_processing::create_sync_data;
+      data_list.push_back(data);
+      return true;
+    }
+    uint32_t id_count = (uint32_t)get_other_signers_id_count(sync_messages);
+    // Do we have sync data from ALL other signers?
+    bool all_sync_data = id_count == (m_num_authorized_signers - 1);
+    // Do we have just ENOUGH sync data to have a minimal viable sync set?
+    // In cases like 2/3 multisig we don't need messages from ALL other signers, only
+    // from enough of them i.e. num_required_signers minus 1 messages
+    bool enough_sync_data = id_count >= (m_num_required_signers - 1);
+    bool sync = false;
+    wait_reason = tr("Syncing not done because multisig sync data from other signers are missing or not complete.");
+    if (all_sync_data)
+    {
+      sync = true;
+    }
+    else if (enough_sync_data)
+    {
+      if (force_sync)
+      {
+        sync = true;
+      }
+      else
+      {
+        // Don't sync, but give a hint how this minimal set COULD be synced if really wanted
+        wait_reason += (boost::format("\nUse \"mms next sync\" if you want to sync with just %s out of %s authorized signers and transact just with them")
+                                     % (m_num_required_signers - 1) % (m_num_authorized_signers - 1)).str();
+      }
+    }
+    if (sync)
+    {
+      processing_data data;
+      data.processing = message_processing::process_sync_data;
+      for (size_t i = 0; i < sync_messages.size(); ++i)
+      {
+        uint32_t id = sync_messages[i];
+        if (id != 0)
+        {
+          data.message_ids.push_back(id);
+        }
+      }
+      data_list.push_back(data);
+      return true;
+    }
+    else
+    {
+      // We can't proceed to any transactions until we have synced; "wait_reason" already set above
+      return false;
+    }
+  }
+
+  bool waiting_found = false;
+  bool note_found = false;
+  bool sync_data_found = false;
+  for (size_t i = 0; i < m_messages.size(); ++i)
+  {
+    message &m = m_messages[i];
+    if (m.state == message_state::waiting)
+    {
+      waiting_found = true;
+      switch (m.type)
+      {
+      case message_type::fully_signed_tx:
+      {
+        // We can either submit it ourselves, or send it to any other signer for submission
+        processing_data data;
+        data.processing = message_processing::submit_tx;
+        data.message_ids.push_back(m.id);
+        data_list.push_back(data);
+
+        data.processing = message_processing::send_tx;
+        for (uint32_t j = 1; j < m_num_authorized_signers; ++j)
+        {
+          data.receiving_signer_index = j;
+          data_list.push_back(data);
+        }
+        return true;
+      }
+
+      case message_type::partially_signed_tx:
+      {
+        if (m.signer_index == 0)
+        {
+          // We started this ourselves, or signed it but with still signatures missing:
+          // We can send it to any other signer for signing / further signing
+          // In principle it does not make sense to send it back to somebody who
+          // already signed, but the MMS does not / not yet keep track of that,
+          // because that would be somewhat complicated.
+          processing_data data;
+          data.processing = message_processing::send_tx;
+          data.message_ids.push_back(m.id);
+          for (uint32_t j = 1; j < m_num_authorized_signers; ++j)
+          {
+            data.receiving_signer_index = j;
+            data_list.push_back(data);
+          }
+          return true;
+        }
+        else
+        {
+          // Somebody else sent this to us: We can sign it
+          // It would be possible to just pass it on, but that's not directly supported here
+          processing_data data;
+          data.processing = message_processing::sign_tx;
+          data.message_ids.push_back(m.id);
+          data_list.push_back(data);
+          return true;
+        }
+      }
+
+      case message_type::note:
+        note_found = true;
+        break;
+
+      case message_type::multisig_sync_data:
+        sync_data_found = true;
+        break;
+
+      default:
+        break;
+      }
+    }
+  }
+  if (waiting_found)
+  {
+    wait_reason = tr("There are waiting messages, but nothing is ready to process under normal circumstances");
+    if (sync_data_found)
+    {
+      wait_reason += tr("\nUse \"mms next sync\" if you want to force processing of the waiting sync data");
+    }
+    if (note_found)
+    {
+      wait_reason += tr("\nUse \"mms note\" to display the waiting notes");
+    }
+  }
+  else
+  {
+    wait_reason = tr("There are no messages waiting to be processed.");
+  }
+
+  return false;
+}
+
+void message_store::set_messages_processed(const processing_data &data)
+{
+  for (size_t i = 0; i < data.message_ids.size(); ++i)
+  {
+    set_message_processed_or_sent(data.message_ids[i]);
+  }
+}
+
+void message_store::set_message_processed_or_sent(uint32_t id)
+{
+  message &m = get_message_ref_by_id(id);
+  if (m.state == message_state::waiting)
+  {
+    // So far a fairly cautious and conservative strategy: Only delete from Bitmessage
+    // when fully processed (and e.g. not already after reception and writing into
+    // the message store file)
+    delete_transport_message(id);
+    m.state = message_state::processed;
+  }
+  else if (m.state == message_state::ready_to_send)
+  {
+    m.state = message_state::sent;
+  }
+  m.modified = (uint64_t)time(NULL);
+}
+
+void message_store::encrypt(crypto::public_key public_key, const std::string &plaintext,
+                            std::string &ciphertext, crypto::public_key &encryption_public_key, crypto::chacha_iv &iv)
+{
+  crypto::secret_key encryption_secret_key;
+  crypto::generate_keys(encryption_public_key, encryption_secret_key);
+
+  crypto::key_derivation derivation;
+  bool success = crypto::generate_key_derivation(public_key, encryption_secret_key, derivation);
+  THROW_WALLET_EXCEPTION_IF(!success, tools::error::wallet_internal_error, "Failed to generate key derivation for message encryption");
+
+  crypto::chacha_key chacha_key;
+  crypto::generate_chacha_key(&derivation, sizeof(derivation), chacha_key, 1);
+  iv = crypto::rand<crypto::chacha_iv>();
+  ciphertext.resize(plaintext.size());
+  crypto::chacha20(plaintext.data(), plaintext.size(), chacha_key, iv, &ciphertext[0]);
+}
+
+void message_store::decrypt(const std::string &ciphertext, const crypto::public_key &encryption_public_key, const crypto::chacha_iv &iv,
+                            const crypto::secret_key &view_secret_key, std::string &plaintext)
+{
+  crypto::key_derivation derivation;
+  bool success = crypto::generate_key_derivation(encryption_public_key, view_secret_key, derivation);
+  THROW_WALLET_EXCEPTION_IF(!success, tools::error::wallet_internal_error, "Failed to generate key derivation for message decryption");
+  crypto::chacha_key chacha_key;
+  crypto::generate_chacha_key(&derivation, sizeof(derivation), chacha_key, 1);
+  plaintext.resize(ciphertext.size());
+  crypto::chacha20(ciphertext.data(), ciphertext.size(), chacha_key, iv, &plaintext[0]);
+}
+
+void message_store::send_message(const multisig_wallet_state &state, uint32_t id)
+{
+  message &m = get_message_ref_by_id(id);
+  const authorized_signer &me = m_signers[0];
+  const authorized_signer &receiver = m_signers[m.signer_index];
+  transport_message dm;
+  crypto::public_key public_key;
+
+  dm.timestamp = (uint64_t)time(NULL);
+  dm.subject = "MMS V0 " + tools::get_human_readable_timestamp(dm.timestamp);
+  dm.source_transport_address = me.transport_address;
+  dm.source_monero_address = me.monero_address;
+  if (m.type == message_type::auto_config_data)
+  {
+    // Encrypt with the public key derived from the auto-config token, and send to the
+    // transport address likewise derived from that token
+    public_key = me.auto_config_public_key;
+    dm.destination_transport_address = me.auto_config_transport_address;
+    // The destination Monero address is not yet known
+    memset(&dm.destination_monero_address, 0, sizeof(cryptonote::account_public_address));
+  }
+  else
+  {
+    // Encrypt with the receiver's view public key
+    public_key = receiver.monero_address.m_view_public_key;
+    const authorized_signer &receiver = m_signers[m.signer_index];
+    dm.destination_monero_address = receiver.monero_address;
+    dm.destination_transport_address = receiver.transport_address;
+  }
+  encrypt(public_key, m.content, dm.content, dm.encryption_public_key, dm.iv);
+  dm.type = (uint32_t)m.type;
+  dm.hash = crypto::cn_fast_hash(dm.content.data(), dm.content.size());
+  dm.round = m.round;
+
+  crypto::generate_signature(dm.hash, me.monero_address.m_view_public_key, state.view_secret_key, dm.signature);
+
+  m_transporter.send_message(dm);
+
+  m.state=message_state::sent;
+  m.sent= (uint64_t)time(NULL);
+}
+
+bool message_store::check_for_messages(const multisig_wallet_state &state, std::vector<message> &messages)
+{
+  m_run.store(true, std::memory_order_relaxed);
+  const authorized_signer &me = m_signers[0];
+  std::vector<std::string> destinations;
+  destinations.push_back(me.transport_address);
+  for (uint32_t i = 1; i < m_num_authorized_signers; ++i)
+  {
+    const authorized_signer &m = m_signers[i];
+    if (m.auto_config_running)
+    {
+      destinations.push_back(m.auto_config_transport_address);
+    }
+  }
+  std::vector<transport_message> transport_messages;
+  bool r = m_transporter.receive_messages(destinations, transport_messages);
+  if (!m_run.load(std::memory_order_relaxed))
+  {
+    // Stop was called, don't waste time processing the messages
+    // (but once started processing them, don't react to stop request anymore, avoid receiving them "partially)"
+    return false;
+  }
+
+  bool new_messages = false;
+  for (size_t i = 0; i < transport_messages.size(); ++i)
+  {
+    transport_message &rm = transport_messages[i];
+    if (any_message_with_hash(rm.hash))
+    {
+      // Already seen, do not take again
+    }
+    else
+    {
+      uint32_t sender_index;
+      bool take = false;
+      message_type type = static_cast<message_type>(rm.type);
+      crypto::secret_key decrypt_key = state.view_secret_key;
+      if (type == message_type::auto_config_data)
+      {
+        // Find out which signer sent it by checking which auto config transport address
+        // the message was sent to
+        for (uint32_t i = 1; i < m_num_authorized_signers; ++i)
+        {
+          const authorized_signer &m = m_signers[i];
+          if (m.auto_config_transport_address == rm.destination_transport_address)
+          {
+            take = true;
+            sender_index = i;
+            decrypt_key = m.auto_config_secret_key;
+            break;
+          }
+        }
+      }
+      else if (type == message_type::signer_config)
+      {
+        // Typically we can't check yet whether we know the sender, so take from any
+        // and pretend it's from "me" because we might have nothing else yet
+        take = true;
+        sender_index = 0;
+      }
+      else
+      {
+        // Only accept from senders that are known as signer here, otherwise just ignore
+        take = get_signer_index_by_monero_address(rm.source_monero_address, sender_index);
+      }
+      if (take && (type != message_type::auto_config_data))
+      {
+        // If the destination address is known, check it as well; this additional filter
+        // allows using the same transport address for multiple signers
+        take = rm.destination_monero_address == me.monero_address;
+      }
+      if (take)
+      {
+        crypto::hash actual_hash = crypto::cn_fast_hash(rm.content.data(), rm.content.size());
+        THROW_WALLET_EXCEPTION_IF(actual_hash != rm.hash, tools::error::wallet_internal_error, "Message hash mismatch");
+
+        bool signature_valid = crypto::check_signature(actual_hash, rm.source_monero_address.m_view_public_key, rm.signature);
+        THROW_WALLET_EXCEPTION_IF(!signature_valid, tools::error::wallet_internal_error, "Message signature not valid");
+
+        std::string plaintext;
+        decrypt(rm.content, rm.encryption_public_key, rm.iv, decrypt_key, plaintext);
+        size_t index = add_message(state, sender_index, (message_type)rm.type, message_direction::in, plaintext);
+        message &m = m_messages[index];
+        m.hash = rm.hash;
+        m.transport_id = rm.transport_id;
+        m.sent = rm.timestamp;
+        m.round = rm.round;
+        m.signature_count = rm.signature_count;
+        messages.push_back(m);
+        new_messages = true;
+      }
+    }
+  }
+  return new_messages;
+}
+
+void message_store::delete_transport_message(uint32_t id)
+{
+  const message &m = get_message_by_id(id);
+  if (!m.transport_id.empty())
+  {
+    m_transporter.delete_message(m.transport_id);
+  }
+}
+
+std::string message_store::account_address_to_string(const cryptonote::account_public_address &account_address) const
+{
+  return get_account_address_as_str(m_nettype, false, account_address);
+}
+
+const char* message_store::message_type_to_string(message_type type)
+{
+  switch (type)
+  {
+  case message_type::key_set:
+    return tr("key set");
+  case message_type::additional_key_set:
+    return tr("additional key set");
+  case message_type::multisig_sync_data:
+    return tr("multisig sync data");
+  case message_type::partially_signed_tx:
+    return tr("partially signed tx");
+  case message_type::fully_signed_tx:
+    return tr("fully signed tx");
+  case message_type::note:
+    return tr("note");
+  case message_type::signer_config:
+    return tr("signer config");
+  case message_type::auto_config_data:
+    return tr("auto-config data");
+  default:
+    return tr("unknown message type");
+  }
+}
+
+const char* message_store::message_direction_to_string(message_direction direction)
+{
+  switch (direction)
+  {
+  case message_direction::in:
+    return tr("in");
+  case message_direction::out:
+    return tr("out");
+  default:
+    return tr("unknown message direction");
+  }
+}
+
+const char* message_store::message_state_to_string(message_state state)
+{
+  switch (state)
+  {
+  case message_state::ready_to_send:
+    return tr("ready to send");
+  case message_state::sent:
+    return tr("sent");
+  case message_state::waiting:
+    return tr("waiting");
+  case message_state::processed:
+    return tr("processed");
+  case message_state::cancelled:
+    return tr("cancelled");
+  default:
+    return tr("unknown message state");
+  }
+}
+
+// Convert a signer to string suitable for a column in a list, with 'max_width'
+// Format: label: transport_address
+std::string message_store::signer_to_string(const authorized_signer &signer, uint32_t max_width)
+{
+  std::string s = "";
+  s.reserve(max_width);
+  uint32_t avail = max_width;
+  uint32_t label_len = signer.label.length();
+  if (label_len > avail)
+  {
+    s.append(signer.label.substr(0, avail - 2));
+    s.append("..");
+    return s;
+  }
+  s.append(signer.label);
+  avail -= label_len;
+  uint32_t transport_addr_len = signer.transport_address.length();
+  if ((transport_addr_len > 0) && (avail > 10))
+  {
+    s.append(": ");
+    avail -= 2;
+    if (transport_addr_len <= avail)
+    {
+      s.append(signer.transport_address);
+    }
+    else
+    {
+      s.append(signer.transport_address.substr(0, avail-2));
+      s.append("..");
+    }
+  }
+  return s;
+}
+
+}