Wallet: Option to export data to ASCII

New CLI wallet variable: export-format with options "binary" (the default),
or "ascii". "Binary" behaves as before, "ascii" forces the wallet to convert
data to ASCII using base64.

Reading files from the disk tries to auto detect what format has been
used (using a magic string added when exporting the data).

Implements https://github.com/monero-project/monero/issues/2859

src/simplewallet/simplewallet.cpp

@@ -1254,7 +1254,7 @@ bool simple_wallet::export_multisig_main(const std::vector<std::string> &args, b
     }
     else
     {
-      bool r = epee::file_io_utils::save_string_to_file(filename, ciphertext);
+      bool r = m_wallet->save_to_file(filename, ciphertext);
       if (!r)
       {
         fail_msg_writer() << tr("failed to save file ") << filename;
@@ -1315,7 +1315,7 @@ bool simple_wallet::import_multisig_main(const std::vector<std::string> &args, b
     {
       const std::string &filename = args[n];
       std::string data;
-      bool r = epee::file_io_utils::load_file_to_string(filename, data);
+      bool r = m_wallet->load_from_file(filename, data);
       if (!r)
       {
         fail_msg_writer() << tr("failed to read file ") << filename;
@@ -1626,7 +1626,7 @@ bool simple_wallet::export_raw_multisig(const std::vector<std::string> &args)
       if (!filenames.empty())
         filenames += ", ";
       filenames += filename;
-      if (!epee::file_io_utils::save_string_to_file(filename, cryptonote::tx_to_blob(ptx.tx)))
+      if (!m_wallet->save_to_file(filename, cryptonote::tx_to_blob(ptx.tx)))
       {
         fail_msg_writer() << tr("Failed to export multisig transaction to file ") << filename;
         return true;
@@ -2712,6 +2712,35 @@ bool simple_wallet::set_device_name(const std::vector<std::string> &args/* = std
   return true;
 }
 
+bool simple_wallet::set_export_format(const std::vector<std::string> &args/* = std::vector<std::string()*/)
+{
+  if (args.size() < 2)
+  {
+    fail_msg_writer() << tr("Export format not specified");
+    return true;
+  }
+
+  if (boost::algorithm::iequals(args[1], "ascii"))
+  {
+    m_wallet->set_export_format(tools::wallet2::ExportFormat::Ascii);
+  }
+  else if (boost::algorithm::iequals(args[1], "binary"))
+  {
+    m_wallet->set_export_format(tools::wallet2::ExportFormat::Binary);
+  }
+  else
+  {
+    fail_msg_writer() << tr("Export format not recognized.");
+    return true;
+  }
+  const auto pwd_container = get_and_verify_password();
+  if (pwd_container)
+  {
+    m_wallet->rewrite(m_wallet_file, pwd_container->password());
+  }
+  return true;
+}
+
 bool simple_wallet::help(const std::vector<std::string> &args/* = std::vector<std::string>()*/)
 {
   if(args.empty())
@@ -2912,7 +2941,9 @@ simple_wallet::simple_wallet()
                                   "setup-background-mining <1|0>\n "
                                   "  Whether to enable background mining. Set this to support the network and to get a chance to receive new monero.\n "
                                   "device-name <device_name[:device_spec]>\n "
-                                  "  Device name for hardware wallet."));
+                                  "  Device name for hardware wallet.\n "
+                                  "export-format <\"binary\"|\"ascii\">\n "
+                                  "  Save all exported files as binary (cannot be copied and pasted) or ascii (can be).\n "));
   m_cmd_binder.set_handler("encrypted_seed",
                            boost::bind(&simple_wallet::encrypted_seed, this, _1),
                            tr("Display the encrypted Electrum-style mnemonic seed."));
@@ -3278,6 +3309,7 @@ bool simple_wallet::set_variable(const std::vector<std::string> &args)
     success_msg_writer() << "track-uses = " << m_wallet->track_uses();
     success_msg_writer() << "setup-background-mining = " << setup_background_mining_string;
     success_msg_writer() << "device-name = " << m_wallet->device_name();
+    success_msg_writer() << "export-format = " << (m_wallet->export_format() == tools::wallet2::ExportFormat::Ascii ? "ascii" : "binary");
     return true;
   }
   else
@@ -3336,6 +3368,7 @@ bool simple_wallet::set_variable(const std::vector<std::string> &args)
     CHECK_SIMPLE_VARIABLE("track-uses", set_track_uses, tr("0 or 1"));
     CHECK_SIMPLE_VARIABLE("setup-background-mining", set_setup_background_mining, tr("1/yes or 0/no"));
     CHECK_SIMPLE_VARIABLE("device-name", set_device_name, tr("<device_name[:device_spec]>"));
+    CHECK_SIMPLE_VARIABLE("export-format", set_export_format, tr("\"binary\" or \"ascii\""));
   }
   fail_msg_writer() << tr("set: unrecognized argument(s)");
   return true;
@@ -7312,7 +7345,7 @@ bool simple_wallet::get_tx_proof(const std::vector<std::string> &args)
   {
     std::string sig_str = m_wallet->get_tx_proof(txid, info.address, info.is_subaddress, args.size() == 3 ? args[2] : "");
     const std::string filename = "monero_tx_proof";
-    if (epee::file_io_utils::save_string_to_file(filename, sig_str))
+    if (m_wallet->save_to_file(filename, sig_str, true))
       success_msg_writer() << tr("signature file saved to: ") << filename;
     else
       fail_msg_writer() << tr("failed to save signature file");
@@ -7440,7 +7473,7 @@ bool simple_wallet::check_tx_proof(const std::vector<std::string> &args)
 
   // read signature file
   std::string sig_str;
-  if (!epee::file_io_utils::load_file_to_string(args[2], sig_str))
+  if (!m_wallet->load_from_file(args[2], sig_str))
   {
     fail_msg_writer() << tr("failed to load signature file");
     return true;
@@ -7524,7 +7557,7 @@ bool simple_wallet::get_spend_proof(const std::vector<std::string> &args)
   {
     const std::string sig_str = m_wallet->get_spend_proof(txid, args.size() == 2 ? args[1] : "");
     const std::string filename = "monero_spend_proof";
-    if (epee::file_io_utils::save_string_to_file(filename, sig_str))
+    if (m_wallet->save_to_file(filename, sig_str, true))
       success_msg_writer() << tr("signature file saved to: ") << filename;
     else
       fail_msg_writer() << tr("failed to save signature file");
@@ -7554,7 +7587,7 @@ bool simple_wallet::check_spend_proof(const std::vector<std::string> &args)
     return true;
 
   std::string sig_str;
-  if (!epee::file_io_utils::load_file_to_string(args[1], sig_str))
+  if (!m_wallet->load_from_file(args[1], sig_str))
   {
     fail_msg_writer() << tr("failed to load signature file");
     return true;
@@ -7613,7 +7646,7 @@ bool simple_wallet::get_reserve_proof(const std::vector<std::string> &args)
   {
     const std::string sig_str = m_wallet->get_reserve_proof(account_minreserve, args.size() == 2 ? args[1] : "");
     const std::string filename = "monero_reserve_proof";
-    if (epee::file_io_utils::save_string_to_file(filename, sig_str))
+    if (m_wallet->save_to_file(filename, sig_str, true))
       success_msg_writer() << tr("signature file saved to: ") << filename;
     else
       fail_msg_writer() << tr("failed to save signature file");
@@ -7648,7 +7681,7 @@ bool simple_wallet::check_reserve_proof(const std::vector<std::string> &args)
   }
 
   std::string sig_str;
-  if (!epee::file_io_utils::load_file_to_string(args[1], sig_str))
+  if (!m_wallet->load_from_file(args[1], sig_str))
   {
     fail_msg_writer() << tr("failed to load signature file");
     return true;
@@ -9011,7 +9044,7 @@ bool simple_wallet::sign(const std::vector<std::string> &args)
 
   std::string filename = args[0];
   std::string data;
-  bool r = epee::file_io_utils::load_file_to_string(filename, data);
+  bool r = m_wallet->load_from_file(filename, data);
   if (!r)
   {
     fail_msg_writer() << tr("failed to read file ") << filename;
@@ -9037,7 +9070,7 @@ bool simple_wallet::verify(const std::vector<std::string> &args)
   std::string signature= args[2];
 
   std::string data;
-  bool r = epee::file_io_utils::load_file_to_string(filename, data);
+  bool r = m_wallet->load_from_file(filename, data);
   if (!r)
   {
     fail_msg_writer() << tr("failed to read file ") << filename;
@@ -9255,7 +9288,7 @@ bool simple_wallet::export_outputs(const std::vector<std::string> &args_)
   try
   {
     std::string data = m_wallet->export_outputs_to_str(all);
-    bool r = epee::file_io_utils::save_string_to_file(filename, data);
+    bool r = m_wallet->save_to_file(filename, data);
     if (!r)
     {
       fail_msg_writer() << tr("failed to save file ") << filename;
@@ -9288,7 +9321,7 @@ bool simple_wallet::import_outputs(const std::vector<std::string> &args)
   std::string filename = args[0];
 
   std::string data;
-  bool r = epee::file_io_utils::load_file_to_string(filename, data);
+  bool r = m_wallet->load_from_file(filename, data);
   if (!r)
   {
     fail_msg_writer() << tr("failed to read file ") << filename;
@@ -9489,7 +9522,7 @@ void simple_wallet::commit_or_save(std::vector<tools::wallet2::pending_tx>& ptx_
       tx_to_blob(ptx.tx, blob);
       const std::string blob_hex = epee::string_tools::buff_to_hex_nodelimer(blob);
       const std::string filename = "raw_monero_tx" + (ptx_vector.size() == 1 ? "" : ("_" + std::to_string(i++)));
-      if (epee::file_io_utils::save_string_to_file(filename, blob_hex))
+      if (m_wallet->save_to_file(filename, blob_hex, true))
         success_msg_writer(true) << tr("Transaction successfully saved to ") << filename << tr(", txid ") << txid;
       else
         fail_msg_writer() << tr("Failed to save transaction to ") << filename << tr(", txid ") << txid;
@@ -10274,7 +10307,7 @@ void simple_wallet::mms_export(const std::vector<std::string> &args)
   if (valid_id)
   {
     const std::string filename = "mms_message_content";
-    if (epee::file_io_utils::save_string_to_file(filename, m.content))
+    if (m_wallet->save_to_file(filename, m.content))
     {
       success_msg_writer() << tr("Message content saved to: ") << filename;
     }

src/simplewallet/simplewallet.h

@@ -146,6 +146,7 @@ namespace cryptonote
     bool set_track_uses(const std::vector<std::string> &args = std::vector<std::string>());
     bool set_setup_background_mining(const std::vector<std::string> &args = std::vector<std::string>());
     bool set_device_name(const std::vector<std::string> &args = std::vector<std::string>());
+    bool set_export_format(const std::vector<std::string> &args = std::vector<std::string>());
     bool help(const std::vector<std::string> &args = std::vector<std::string>());
     bool start_mining(const std::vector<std::string> &args);
     bool stop_mining(const std::vector<std::string> &args);

src/wallet/wallet2.cpp

@@ -40,6 +40,7 @@
 #include <boost/asio/ip/address.hpp>
 #include <boost/range/adaptor/transformed.hpp>
 #include <boost/preprocessor/stringize.hpp>
+#include <openssl/evp.h>
 #include "include_base_utils.h"
 using namespace epee;
 
@@ -138,6 +139,8 @@ using namespace cryptonote;
 static const std::string MULTISIG_SIGNATURE_MAGIC = "SigMultisigPkV1";
 static const std::string MULTISIG_EXTRA_INFO_MAGIC = "MultisigxV1";
 
+static const std::string ASCII_OUTPUT_MAGIC = "MoneroAsciiDataV1";
+
 namespace
 {
   std::string get_default_ringdb_path()
@@ -1143,7 +1146,8 @@ wallet2::wallet2(network_type nettype, uint64_t kdf_rounds, bool unattended):
   m_device_last_key_image_sync(0),
   m_use_dns(true),
   m_offline(false),
-  m_rpc_version(0)
+  m_rpc_version(0),
+  m_export_format(ExportFormat::Binary)
 {
 }
 
@@ -3647,6 +3651,9 @@ bool wallet2::store_keys(const std::string& keys_file_name, const epee::wipeable
   value2.SetInt(m_original_keys_available ? 1 : 0);
   json.AddMember("original_keys_available", value2, json.GetAllocator());
 
+  value2.SetInt(m_export_format);
+  json.AddMember("export_format", value2, json.GetAllocator());
+
   value2.SetUint(1);
   json.AddMember("encrypted_secret_keys", value2, json.GetAllocator());
 
@@ -3684,7 +3691,7 @@ bool wallet2::store_keys(const std::string& keys_file_name, const epee::wipeable
   std::string tmp_file_name = keys_file_name + ".new";
   std::string buf;
   r = ::serialization::dump_binary(keys_file_data, buf);
-  r = r && epee::file_io_utils::save_string_to_file(tmp_file_name, buf);
+  r = r && save_to_file(tmp_file_name, buf);
   CHECK_AND_ASSERT_MES(r, false, "failed to generate wallet keys file " << tmp_file_name);
 
   unlock_keys_file();
@@ -3741,7 +3748,7 @@ bool wallet2::load_keys(const std::string& keys_file_name, const epee::wipeable_
   wallet2::keys_file_data keys_file_data;
   std::string buf;
   bool encrypted_secret_keys = false;
-  bool r = epee::file_io_utils::load_file_to_string(keys_file_name, buf);
+  bool r = load_from_file(keys_file_name, buf);
   THROW_WALLET_EXCEPTION_IF(!r, error::file_read_error, keys_file_name);
 
   // Decrypt the contents
@@ -3754,7 +3761,6 @@ bool wallet2::load_keys(const std::string& keys_file_name, const epee::wipeable_
   crypto::chacha20(keys_file_data.account_data.data(), keys_file_data.account_data.size(), key, keys_file_data.iv, &account_data[0]);
   if (json.Parse(account_data.c_str()).HasParseError() || !json.IsObject())
     crypto::chacha8(keys_file_data.account_data.data(), keys_file_data.account_data.size(), key, keys_file_data.iv, &account_data[0]);
-
   // The contents should be JSON if the wallet follows the new format.
   if (json.Parse(account_data.c_str()).HasParseError())
   {
@@ -3793,6 +3799,7 @@ bool wallet2::load_keys(const std::string& keys_file_name, const epee::wipeable_
     m_subaddress_lookahead_major = SUBADDRESS_LOOKAHEAD_MAJOR;
     m_subaddress_lookahead_minor = SUBADDRESS_LOOKAHEAD_MINOR;
     m_original_keys_available = false;
+    m_export_format = ExportFormat::Binary;
     m_device_name = "";
     m_device_derivation_path = "";
     m_key_device_type = hw::device::device_type::SOFTWARE;
@@ -3954,6 +3961,9 @@ bool wallet2::load_keys(const std::string& keys_file_name, const epee::wipeable_
     GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, encrypted_secret_keys, uint32_t, Uint, false, false);
     encrypted_secret_keys = field_encrypted_secret_keys;
 
+    GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, export_format, ExportFormat, Int, false, Binary);
+    m_export_format = field_export_format;
+
     GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, device_name, std::string, String, false, std::string());
     if (m_device_name.empty())
     {
@@ -4101,7 +4111,7 @@ bool wallet2::verify_password(const std::string& keys_file_name, const epee::wip
   wallet2::keys_file_data keys_file_data;
   std::string buf;
   bool encrypted_secret_keys = false;
-  bool r = epee::file_io_utils::load_file_to_string(keys_file_name, buf);
+  bool r = load_from_file(keys_file_name, buf);
   THROW_WALLET_EXCEPTION_IF(!r, error::file_read_error, keys_file_name);
 
   // Decrypt the contents
@@ -4186,7 +4196,7 @@ void wallet2::create_keys_file(const std::string &wallet_, bool watch_only, cons
 
     if (create_address_file)
     {
-      r = file_io_utils::save_string_to_file(m_wallet_file + ".address.txt", m_account.get_public_address_str(m_nettype));
+      r = save_to_file(m_wallet_file + ".address.txt", m_account.get_public_address_str(m_nettype), true);
       if(!r) MERROR("String with address text not saved");
     }
   }
@@ -4208,7 +4218,7 @@ bool wallet2::query_device(hw::device::device_type& device_type, const std::stri
   rapidjson::Document json;
   wallet2::keys_file_data keys_file_data;
   std::string buf;
-  bool r = epee::file_io_utils::load_file_to_string(keys_file_name, buf);
+  bool r = load_from_file(keys_file_name, buf);
   THROW_WALLET_EXCEPTION_IF(!r, error::file_read_error, keys_file_name);
 
   // Decrypt the contents
@@ -4757,7 +4767,7 @@ std::string wallet2::exchange_multisig_keys(const epee::wipeable_string &passwor
 
       if (boost::filesystem::exists(m_wallet_file + ".address.txt"))
       {
-        r = file_io_utils::save_string_to_file(m_wallet_file + ".address.txt", m_account.get_public_address_str(m_nettype));
+        r = save_to_file(m_wallet_file + ".address.txt", m_account.get_public_address_str(m_nettype), true);
         if(!r) MERROR("String with address text not saved");
       }
     }
@@ -5266,7 +5276,7 @@ void wallet2::load(const std::string& wallet_, const epee::wipeable_string& pass
   {
     wallet2::cache_file_data cache_file_data;
     std::string buf;
-    bool r = epee::file_io_utils::load_file_to_string(m_wallet_file, buf, std::numeric_limits<size_t>::max());
+    bool r = load_from_file(m_wallet_file, buf, std::numeric_limits<size_t>::max());
     THROW_WALLET_EXCEPTION_IF(!r, error::file_read_error, m_wallet_file);
 
     // try to read it as an encrypted cache
@@ -5501,7 +5511,7 @@ void wallet2::store_to(const std::string &path, const epee::wipeable_string &pas
     {
       // save address to the new file
       const std::string address_file = m_wallet_file + ".address.txt";
-      r = file_io_utils::save_string_to_file(address_file, m_account.get_public_address_str(m_nettype));
+      r = save_to_file(address_file, m_account.get_public_address_str(m_nettype), true);
       THROW_WALLET_EXCEPTION_IF(!r, error::file_save_error, m_wallet_file);
     }
     // remove old wallet file
@@ -5536,7 +5546,7 @@ void wallet2::store_to(const std::string &path, const epee::wipeable_string &pas
     binary_archive<true> oar(oss);
     bool success = ::serialization::serialize(oar, cache_file_data);
     if (success) {
-        success = epee::file_io_utils::save_string_to_file(new_file, oss.str());
+        success = save_to_file(new_file, oss.str());
     }
     THROW_WALLET_EXCEPTION_IF(!success, error::file_save_error, new_file);
 #else
@@ -6164,7 +6174,7 @@ bool wallet2::save_tx(const std::vector<pending_tx>& ptx_vector, const std::stri
   std::string ciphertext = dump_tx_to_str(ptx_vector);
   if (ciphertext.empty())
     return false;
-  return epee::file_io_utils::save_string_to_file(filename, ciphertext);
+  return save_to_file(filename, ciphertext);
 }
 //----------------------------------------------------------------------------------------------------
 std::string wallet2::dump_tx_to_str(const std::vector<pending_tx> &ptx_vector) const
@@ -6206,7 +6216,7 @@ bool wallet2::load_unsigned_tx(const std::string &unsigned_filename, unsigned_tx
     LOG_PRINT_L0("File " << unsigned_filename << " does not exist: " << errcode);
     return false;
   }
-  if (!epee::file_io_utils::load_file_to_string(unsigned_filename.c_str(), s))
+  if (!load_from_file(unsigned_filename.c_str(), s))
   {
     LOG_PRINT_L0("Failed to load from " << unsigned_filename);
     return false;
@@ -6427,7 +6437,7 @@ bool wallet2::sign_tx(unsigned_tx_set &exported_txs, const std::string &signed_f
     return false;
   }
 
-  if (!epee::file_io_utils::save_string_to_file(signed_filename, ciphertext))
+  if (!save_to_file(signed_filename, ciphertext))
   {
     LOG_PRINT_L0("Failed to save file to " << signed_filename);
     return false;
@@ -6439,7 +6449,7 @@ bool wallet2::sign_tx(unsigned_tx_set &exported_txs, const std::string &signed_f
     {
       std::string tx_as_hex = epee::string_tools::buff_to_hex_nodelimer(tx_to_blob(signed_txes.ptx[i].tx));
       std::string raw_filename = signed_filename + "_raw" + (signed_txes.ptx.size() == 1 ? "" : ("_" + std::to_string(i)));
-      if (!epee::file_io_utils::save_string_to_file(raw_filename, tx_as_hex))
+      if (!save_to_file(raw_filename, tx_as_hex))
       {
         LOG_PRINT_L0("Failed to save file to " << raw_filename);
         return false;
@@ -6487,7 +6497,7 @@ bool wallet2::load_tx(const std::string &signed_filename, std::vector<tools::wal
     return false;
   }
 
-  if (!epee::file_io_utils::load_file_to_string(signed_filename.c_str(), s))
+  if (!load_from_file(signed_filename.c_str(), s))
   {
     LOG_PRINT_L0("Failed to load from " << signed_filename);
     return false;
@@ -6618,7 +6628,7 @@ bool wallet2::save_multisig_tx(const multisig_tx_set &txs, const std::string &fi
   std::string ciphertext = save_multisig_tx(txs);
   if (ciphertext.empty())
     return false;
-  return epee::file_io_utils::save_string_to_file(filename, ciphertext);
+  return save_to_file(filename, ciphertext);
 }
 //----------------------------------------------------------------------------------------------------
 wallet2::multisig_tx_set wallet2::make_multisig_tx_set(const std::vector<pending_tx>& ptx_vector) const
@@ -6646,7 +6656,7 @@ bool wallet2::save_multisig_tx(const std::vector<pending_tx>& ptx_vector, const
   std::string ciphertext = save_multisig_tx(ptx_vector);
   if (ciphertext.empty())
     return false;
-  return epee::file_io_utils::save_string_to_file(filename, ciphertext);
+  return save_to_file(filename, ciphertext);
 }
 //----------------------------------------------------------------------------------------------------
 bool wallet2::parse_multisig_tx_from_str(std::string multisig_tx_st, multisig_tx_set &exported_txs) const
@@ -6737,7 +6747,7 @@ bool wallet2::load_multisig_tx_from_file(const std::string &filename, multisig_t
     LOG_PRINT_L0("File " << filename << " does not exist: " << errcode);
     return false;
   }
-  if (!epee::file_io_utils::load_file_to_string(filename.c_str(), s))
+  if (!load_from_file(filename.c_str(), s))
   {
     LOG_PRINT_L0("Failed to load from " << filename);
     return false;
@@ -11633,7 +11643,7 @@ bool wallet2::export_key_images(const std::string &filename, bool all) const
   // encrypt data, keep magic plaintext
   PERF_TIMER(export_key_images_encrypt);
   std::string ciphertext = encrypt_with_view_secret_key(data);
-  return epee::file_io_utils::save_string_to_file(filename, magic + ciphertext);    
+  return save_to_file(filename, magic + ciphertext);
 }
 
 //----------------------------------------------------------------------------------------------------
@@ -11698,7 +11708,7 @@ uint64_t wallet2::import_key_images(const std::string &filename, uint64_t &spent
 {
   PERF_TIMER(import_key_images_fsu);
   std::string data;
-  bool r = epee::file_io_utils::load_file_to_string(filename, data);
+  bool r = load_from_file(filename, data);
 
   THROW_WALLET_EXCEPTION_IF(!r, error::wallet_internal_error, std::string(tr("failed to read file ")) + filename);
 
@@ -13102,6 +13112,83 @@ void wallet2::throw_on_rpc_response_error(const boost::optional<std::string> &st
   THROW_WALLET_EXCEPTION_IF(*status != CORE_RPC_STATUS_OK, tools::error::wallet_generic_rpc_error, method, m_trusted_daemon ? *status : "daemon error");
 }
 //----------------------------------------------------------------------------------------------------
+
+bool wallet2::save_to_file(const std::string& path_to_file, const std::string& raw, bool is_printable) const
+{
+  if (is_printable || m_export_format == ExportFormat::Binary)
+  {
+    return epee::file_io_utils::save_string_to_file(path_to_file, raw);
+  }
+
+  FILE *fp = fopen(path_to_file.c_str(), "w+");
+  // Save the result b/c we need to close the fp before returning success/failure.
+  int write_result = PEM_write(fp, ASCII_OUTPUT_MAGIC.c_str(), "", (const unsigned char *) raw.c_str(), raw.length());
+  fclose(fp);
+
+  if (write_result == 0)
+  {
+    return false;
+  }
+  else
+  {
+    return true;
+  }
+}
+//----------------------------------------------------------------------------------------------------
+
+bool wallet2::load_from_file(const std::string& path_to_file, std::string& target_str,
+                             size_t max_size)
+{
+  std::string data;
+  bool r = epee::file_io_utils::load_file_to_string(path_to_file, data, max_size);
+  if (!r)
+  {
+    return false;
+  }
+
+  if (!boost::algorithm::contains(boost::make_iterator_range(data.begin(), data.end()), ASCII_OUTPUT_MAGIC))
+  {
+    // It's NOT our ascii dump.
+    target_str = std::move(data);
+    return true;
+  }
+
+  // Creating a BIO and calling PEM_read_bio instead of simpler PEM_read
+  // to avoid reading the file from disk twice.
+  BIO* b = BIO_new_mem_buf((const void*) data.data(), data.length());
+
+  char *name = NULL;
+  char *header = NULL;
+  unsigned char *openssl_data = NULL;
+  long len = 0;
+
+  // Save the result b/c we need to free the data before returning success/failure.
+  int success = PEM_read_bio(b, &name, &header, &openssl_data, &len);
+
+  try
+  {
+    target_str = std::string((const char*) openssl_data, len);
+  }
+  catch (...)
+  {
+    success = 0;
+  }
+
+  OPENSSL_free((void *) name);
+  OPENSSL_free((void *) header);
+  OPENSSL_free((void *) openssl_data);
+  BIO_free(b);
+
+  if (success == 0)
+  {
+    return false;
+  }
+  else
+  {
+    return true;
+  }
+}
+//----------------------------------------------------------------------------------------------------
 void wallet2::hash_m_transfer(const transfer_details & transfer, crypto::hash &hash) const
 {
   KECCAK_CTX state;

src/wallet/wallet2.h

@@ -227,6 +227,11 @@ private:
       BackgroundMiningNo = 2,
     };
 
+    enum ExportFormat {
+      Binary = 0,
+      Ascii,
+    };
+
     static const char* tr(const char* str);
 
     static bool has_testnet_option(const boost::program_options::variables_map& vm);
@@ -1050,6 +1055,8 @@ private:
     void device_name(const std::string & device_name) { m_device_name = device_name; }
     const std::string & device_derivation_path() const { return m_device_derivation_path; }
     void device_derivation_path(const std::string &device_derivation_path) { m_device_derivation_path = device_derivation_path; }
+    const ExportFormat & export_format() const { return m_export_format; }
+    inline void set_export_format(const ExportFormat& export_format) { m_export_format = export_format; }
 
     bool get_tx_key_cached(const crypto::hash &txid, crypto::secret_key &tx_key, std::vector<crypto::secret_key> &additional_tx_keys) const;
     void set_tx_key(const crypto::hash &txid, const crypto::secret_key &tx_key, const std::vector<crypto::secret_key> &additional_tx_keys);
@@ -1300,6 +1307,9 @@ private:
     bool frozen(const crypto::key_image &ki) const;
     bool frozen(const transfer_details &td) const;
 
+    bool save_to_file(const std::string& path_to_file, const std::string& binary, bool is_printable = false) const;
+    static bool load_from_file(const std::string& path_to_file, std::string& target_str, size_t max_size = 1000000000);
+
     uint64_t get_bytes_sent() const;
     uint64_t get_bytes_received() const;
 
@@ -1546,6 +1556,8 @@ private:
 
     std::shared_ptr<tools::Notify> m_tx_notify;
     std::unique_ptr<wallet_device_callback> m_device_callback;
+
+    ExportFormat m_export_format;
   };
 }
 BOOST_CLASS_VERSION(tools::wallet2, 28)