// Copyright (c) 2014-2017, 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.
// 
// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers

#include "include_base_utils.h"
using namespace epee;

#include <atomic>
#include "wipeable_string.h"
#include "cryptonote_format_utils.h"
#include "cryptonote_config.h"
#include "crypto/crypto.h"
#include "crypto/hash.h"
#include "ringct/rctSigs.h"

#undef MONERO_DEFAULT_LOG_CATEGORY
#define MONERO_DEFAULT_LOG_CATEGORY "cn"

#define ENCRYPTED_PAYMENT_ID_TAIL 0x8d

// #define ENABLE_HASH_CASH_INTEGRITY_CHECK

using namespace crypto;

static const uint64_t valid_decomposed_outputs[] = {
  (uint64_t)1, (uint64_t)2, (uint64_t)3, (uint64_t)4, (uint64_t)5, (uint64_t)6, (uint64_t)7, (uint64_t)8, (uint64_t)9, // 1 piconero
  (uint64_t)10, (uint64_t)20, (uint64_t)30, (uint64_t)40, (uint64_t)50, (uint64_t)60, (uint64_t)70, (uint64_t)80, (uint64_t)90,
  (uint64_t)100, (uint64_t)200, (uint64_t)300, (uint64_t)400, (uint64_t)500, (uint64_t)600, (uint64_t)700, (uint64_t)800, (uint64_t)900,
  (uint64_t)1000, (uint64_t)2000, (uint64_t)3000, (uint64_t)4000, (uint64_t)5000, (uint64_t)6000, (uint64_t)7000, (uint64_t)8000, (uint64_t)9000,
  (uint64_t)10000, (uint64_t)20000, (uint64_t)30000, (uint64_t)40000, (uint64_t)50000, (uint64_t)60000, (uint64_t)70000, (uint64_t)80000, (uint64_t)90000,
  (uint64_t)100000, (uint64_t)200000, (uint64_t)300000, (uint64_t)400000, (uint64_t)500000, (uint64_t)600000, (uint64_t)700000, (uint64_t)800000, (uint64_t)900000,
  (uint64_t)1000000, (uint64_t)2000000, (uint64_t)3000000, (uint64_t)4000000, (uint64_t)5000000, (uint64_t)6000000, (uint64_t)7000000, (uint64_t)8000000, (uint64_t)9000000, // 1 micronero
  (uint64_t)10000000, (uint64_t)20000000, (uint64_t)30000000, (uint64_t)40000000, (uint64_t)50000000, (uint64_t)60000000, (uint64_t)70000000, (uint64_t)80000000, (uint64_t)90000000,
  (uint64_t)100000000, (uint64_t)200000000, (uint64_t)300000000, (uint64_t)400000000, (uint64_t)500000000, (uint64_t)600000000, (uint64_t)700000000, (uint64_t)800000000, (uint64_t)900000000,
  (uint64_t)1000000000, (uint64_t)2000000000, (uint64_t)3000000000, (uint64_t)4000000000, (uint64_t)5000000000, (uint64_t)6000000000, (uint64_t)7000000000, (uint64_t)8000000000, (uint64_t)9000000000,
  (uint64_t)10000000000, (uint64_t)20000000000, (uint64_t)30000000000, (uint64_t)40000000000, (uint64_t)50000000000, (uint64_t)60000000000, (uint64_t)70000000000, (uint64_t)80000000000, (uint64_t)90000000000,
  (uint64_t)100000000000, (uint64_t)200000000000, (uint64_t)300000000000, (uint64_t)400000000000, (uint64_t)500000000000, (uint64_t)600000000000, (uint64_t)700000000000, (uint64_t)800000000000, (uint64_t)900000000000,
  (uint64_t)1000000000000, (uint64_t)2000000000000, (uint64_t)3000000000000, (uint64_t)4000000000000, (uint64_t)5000000000000, (uint64_t)6000000000000, (uint64_t)7000000000000, (uint64_t)8000000000000, (uint64_t)9000000000000, // 1 monero
  (uint64_t)10000000000000, (uint64_t)20000000000000, (uint64_t)30000000000000, (uint64_t)40000000000000, (uint64_t)50000000000000, (uint64_t)60000000000000, (uint64_t)70000000000000, (uint64_t)80000000000000, (uint64_t)90000000000000,
  (uint64_t)100000000000000, (uint64_t)200000000000000, (uint64_t)300000000000000, (uint64_t)400000000000000, (uint64_t)500000000000000, (uint64_t)600000000000000, (uint64_t)700000000000000, (uint64_t)800000000000000, (uint64_t)900000000000000,
  (uint64_t)1000000000000000, (uint64_t)2000000000000000, (uint64_t)3000000000000000, (uint64_t)4000000000000000, (uint64_t)5000000000000000, (uint64_t)6000000000000000, (uint64_t)7000000000000000, (uint64_t)8000000000000000, (uint64_t)9000000000000000,
  (uint64_t)10000000000000000, (uint64_t)20000000000000000, (uint64_t)30000000000000000, (uint64_t)40000000000000000, (uint64_t)50000000000000000, (uint64_t)60000000000000000, (uint64_t)70000000000000000, (uint64_t)80000000000000000, (uint64_t)90000000000000000,
  (uint64_t)100000000000000000, (uint64_t)200000000000000000, (uint64_t)300000000000000000, (uint64_t)400000000000000000, (uint64_t)500000000000000000, (uint64_t)600000000000000000, (uint64_t)700000000000000000, (uint64_t)800000000000000000, (uint64_t)900000000000000000,
  (uint64_t)1000000000000000000, (uint64_t)2000000000000000000, (uint64_t)3000000000000000000, (uint64_t)4000000000000000000, (uint64_t)5000000000000000000, (uint64_t)6000000000000000000, (uint64_t)7000000000000000000, (uint64_t)8000000000000000000, (uint64_t)9000000000000000000, // 1 meganero
  (uint64_t)10000000000000000000ull
};

static std::atomic<unsigned int> default_decimal_point(CRYPTONOTE_DISPLAY_DECIMAL_POINT);

static std::atomic<uint64_t> tx_hashes_calculated_count(0);
static std::atomic<uint64_t> tx_hashes_cached_count(0);
static std::atomic<uint64_t> block_hashes_calculated_count(0);
static std::atomic<uint64_t> block_hashes_cached_count(0);

namespace cryptonote
{
  //---------------------------------------------------------------
  void get_transaction_prefix_hash(const transaction_prefix& tx, crypto::hash& h)
  {
    std::ostringstream s;
    binary_archive<true> a(s);
    ::serialization::serialize(a, const_cast<transaction_prefix&>(tx));
    crypto::cn_fast_hash(s.str().data(), s.str().size(), h);
  }
  //---------------------------------------------------------------
  crypto::hash get_transaction_prefix_hash(const transaction_prefix& tx)
  {
    crypto::hash h = null_hash;
    get_transaction_prefix_hash(tx, h);
    return h;
  }
  //---------------------------------------------------------------
  bool parse_and_validate_tx_from_blob(const blobdata& tx_blob, transaction& tx)
  {
    std::stringstream ss;
    ss << tx_blob;
    binary_archive<false> ba(ss);
    bool r = ::serialization::serialize(ba, tx);
    CHECK_AND_ASSERT_MES(r, false, "Failed to parse transaction from blob");
    tx.invalidate_hashes();
    return true;
  }
  //---------------------------------------------------------------
  bool parse_and_validate_tx_base_from_blob(const blobdata& tx_blob, transaction& tx)
  {
    std::stringstream ss;
    ss << tx_blob;
    binary_archive<false> ba(ss);
    bool r = tx.serialize_base(ba);
    CHECK_AND_ASSERT_MES(r, false, "Failed to parse transaction from blob");
    return true;
  }
  //---------------------------------------------------------------
  bool parse_and_validate_tx_from_blob(const blobdata& tx_blob, transaction& tx, crypto::hash& tx_hash, crypto::hash& tx_prefix_hash)
  {
    std::stringstream ss;
    ss << tx_blob;
    binary_archive<false> ba(ss);
    bool r = ::serialization::serialize(ba, tx);
    CHECK_AND_ASSERT_MES(r, false, "Failed to parse transaction from blob");
    tx.invalidate_hashes();
    //TODO: validate tx

    get_transaction_hash(tx, tx_hash);
    get_transaction_prefix_hash(tx, tx_prefix_hash);
    return true;
  }
  //---------------------------------------------------------------
  crypto::secret_key get_subaddress_secret_key(const crypto::secret_key& a, const subaddress_index& index)
  {
    const char prefix[] = "SubAddr";
    char data[sizeof(prefix) + sizeof(crypto::secret_key) + sizeof(subaddress_index)];
    memcpy(data, prefix, sizeof(prefix));
    memcpy(data + sizeof(prefix), &a, sizeof(crypto::secret_key));
    memcpy(data + sizeof(prefix) + sizeof(crypto::secret_key), &index, sizeof(subaddress_index));
    crypto::secret_key m;
    crypto::hash_to_scalar(data, sizeof(data), m);
    return m;
  }
  //---------------------------------------------------------------
  bool generate_key_image_helper(const account_keys& ack, 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, 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 << ")");

    std::vector<crypto::key_derivation> additional_recv_derivations;
    for (size_t i = 0; i < additional_tx_public_keys.size(); ++i)
    {
      crypto::key_derivation additional_recv_derivation = AUTO_VAL_INIT(additional_recv_derivation);
      r = crypto::generate_key_derivation(additional_tx_public_keys[i], ack.m_view_secret_key, additional_recv_derivation);
      CHECK_AND_ASSERT_MES(r, false, "key image helper: failed to generate_key_derivation(" << additional_tx_public_keys[i] << ", " << ack.m_view_secret_key << ")");
      additional_recv_derivations.push_back(additional_recv_derivation);
    }

    boost::optional<subaddress_receive_info> subaddr_recv_info = is_out_to_acc_precomp(subaddresses, out_key, recv_derivation, additional_recv_derivations, real_output_index);
    CHECK_AND_ASSERT_MES(subaddr_recv_info, false, "key image helper: given output pubkey doesn't seem to belong to this address");

    return generate_key_image_helper_precomp(ack, out_key, subaddr_recv_info->derivation, real_output_index, subaddr_recv_info->index, in_ephemeral, ki);
  }
  //---------------------------------------------------------------
  bool generate_key_image_helper_precomp(const account_keys& ack, const crypto::public_key& out_key, const crypto::key_derivation& recv_derivation, size_t real_output_index, const subaddress_index& received_index, keypair& in_ephemeral, crypto::key_image& ki)
  {
    if (ack.m_spend_secret_key == crypto::null_skey)
    {
      // for watch-only wallet, simply copy the known output pubkey
      in_ephemeral.pub = out_key;
      in_ephemeral.sec = crypto::null_skey;
    }
    else
    {
      // derive secret key with subaddress - step 1: original CN derivation
      crypto::secret_key scalar_step1;
      crypto::derive_secret_key(recv_derivation, real_output_index, ack.m_spend_secret_key, scalar_step1); // computes Hs(a*R || idx) + b

      // step 2: add Hs(a || index_major || index_minor)
      crypto::secret_key scalar_step2;
      if (received_index.is_zero())
      {
        scalar_step2 = scalar_step1;    // treat index=(0,0) as a special case representing the main address
      }
      else
      {
        crypto::secret_key m = get_subaddress_secret_key(ack.m_view_secret_key, received_index);
        sc_add((unsigned char*)&scalar_step2, (unsigned char*)&scalar_step1, (unsigned char*)&m);
      }

      in_ephemeral.sec = scalar_step2;
      crypto::secret_key_to_public_key(in_ephemeral.sec, in_ephemeral.pub);
      CHECK_AND_ASSERT_MES(in_ephemeral.pub == out_key, false, "key image helper precomp: given output pubkey doesn't match the derived one");
    }

    crypto::generate_key_image(in_ephemeral.pub, in_ephemeral.sec, ki);
    return true;
  }
  //---------------------------------------------------------------
  uint64_t power_integral(uint64_t a, uint64_t b)
  {
    if(b == 0)
      return 1;
    uint64_t total = a;
    for(uint64_t i = 1; i != b; i++)
      total *= a;
    return total;
  }
  //---------------------------------------------------------------
  bool parse_amount(uint64_t& amount, const std::string& str_amount_)
  {
    std::string str_amount = str_amount_;
    boost::algorithm::trim(str_amount);

    size_t point_index = str_amount.find_first_of('.');
    size_t fraction_size;
    if (std::string::npos != point_index)
    {
      fraction_size = str_amount.size() - point_index - 1;
      while (default_decimal_point < fraction_size && '0' == str_amount.back())
      {
        str_amount.erase(str_amount.size() - 1, 1);
        --fraction_size;
      }
      if (default_decimal_point < fraction_size)
        return false;
      str_amount.erase(point_index, 1);
    }
    else
    {
      fraction_size = 0;
    }

    if (str_amount.empty())
      return false;

    if (fraction_size < default_decimal_point)
    {
      str_amount.append(default_decimal_point - fraction_size, '0');
    }

    return string_tools::get_xtype_from_string(amount, str_amount);
  }
  //---------------------------------------------------------------
  bool get_tx_fee(const transaction& tx, uint64_t & fee)
  {
    if (tx.version > 1)
    {
      fee = tx.rct_signatures.txnFee;
      return true;
    }
    uint64_t amount_in = 0;
    uint64_t amount_out = 0;
    for(auto& in: tx.vin)
    {
      CHECK_AND_ASSERT_MES(in.type() == typeid(txin_to_key), 0, "unexpected type id in transaction");
      amount_in += boost::get<txin_to_key>(in).amount;
    }
    for(auto& o: tx.vout)
      amount_out += o.amount;

    CHECK_AND_ASSERT_MES(amount_in >= amount_out, false, "transaction spend (" <<amount_in << ") more than it has (" << amount_out << ")");
    fee = amount_in - amount_out;
    return true;
  }
  //---------------------------------------------------------------
  uint64_t get_tx_fee(const transaction& tx)
  {
    uint64_t r = 0;
    if(!get_tx_fee(tx, r))
      return 0;
    return r;
  }
  //---------------------------------------------------------------
  bool parse_tx_extra(const std::vector<uint8_t>& tx_extra, std::vector<tx_extra_field>& tx_extra_fields)
  {
    tx_extra_fields.clear();

    if(tx_extra.empty())
      return true;

    std::string extra_str(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size());
    std::istringstream iss(extra_str);
    binary_archive<false> ar(iss);

    bool eof = false;
    while (!eof)
    {
      tx_extra_field field;
      bool r = ::do_serialize(ar, field);
      CHECK_AND_NO_ASSERT_MES_L1(r, false, "failed to deserialize extra field. extra = " << string_tools::buff_to_hex_nodelimer(std::string(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size())));
      tx_extra_fields.push_back(field);

      std::ios_base::iostate state = iss.rdstate();
      eof = (EOF == iss.peek());
      iss.clear(state);
    }
    CHECK_AND_NO_ASSERT_MES_L1(::serialization::check_stream_state(ar), false, "failed to deserialize extra field. extra = " << string_tools::buff_to_hex_nodelimer(std::string(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size())));

    return true;
  }
  //---------------------------------------------------------------
  crypto::public_key get_tx_pub_key_from_extra(const std::vector<uint8_t>& tx_extra, size_t pk_index)
  {
    std::vector<tx_extra_field> tx_extra_fields;
    parse_tx_extra(tx_extra, tx_extra_fields);

    tx_extra_pub_key pub_key_field;
    if(!find_tx_extra_field_by_type(tx_extra_fields, pub_key_field, pk_index))
      return null_pkey;

    return pub_key_field.pub_key;
  }
  //---------------------------------------------------------------
  crypto::public_key get_tx_pub_key_from_extra(const transaction_prefix& tx_prefix, size_t pk_index)
  {
    return get_tx_pub_key_from_extra(tx_prefix.extra, pk_index);
  }
  //---------------------------------------------------------------
  crypto::public_key get_tx_pub_key_from_extra(const transaction& tx, size_t pk_index)
  {
    return get_tx_pub_key_from_extra(tx.extra, pk_index);
  }
  //---------------------------------------------------------------
  bool add_tx_pub_key_to_extra(transaction& tx, const crypto::public_key& tx_pub_key)
  {
    return add_tx_pub_key_to_extra(tx.extra, tx_pub_key);
  }
  //---------------------------------------------------------------
  bool add_tx_pub_key_to_extra(transaction_prefix& tx, const crypto::public_key& tx_pub_key)
  {
    return add_tx_pub_key_to_extra(tx.extra, tx_pub_key);
  }
  //---------------------------------------------------------------
  bool add_tx_pub_key_to_extra(std::vector<uint8_t>& tx_extra, const crypto::public_key& tx_pub_key)
  {
    tx_extra.resize(tx_extra.size() + 1 + sizeof(crypto::public_key));
    tx_extra[tx_extra.size() - 1 - sizeof(crypto::public_key)] = TX_EXTRA_TAG_PUBKEY;
    *reinterpret_cast<crypto::public_key*>(&tx_extra[tx_extra.size() - sizeof(crypto::public_key)]) = tx_pub_key;
    return true;
  }
  //---------------------------------------------------------------
  std::vector<crypto::public_key> get_additional_tx_pub_keys_from_extra(const std::vector<uint8_t>& tx_extra)
  {
    // parse
    std::vector<tx_extra_field> tx_extra_fields;
    parse_tx_extra(tx_extra, tx_extra_fields);
    // find corresponding field
    tx_extra_additional_pub_keys additional_pub_keys;
    if(!find_tx_extra_field_by_type(tx_extra_fields, additional_pub_keys))
      return {};
    return additional_pub_keys.data;
  }
  //---------------------------------------------------------------
  std::vector<crypto::public_key> get_additional_tx_pub_keys_from_extra(const transaction_prefix& tx)
  {
    return get_additional_tx_pub_keys_from_extra(tx.extra);
  }
  //---------------------------------------------------------------
  bool add_additional_tx_pub_keys_to_extra(std::vector<uint8_t>& tx_extra, const std::vector<crypto::public_key>& additional_pub_keys)
  {
    // convert to variant
    tx_extra_field field = tx_extra_additional_pub_keys{ additional_pub_keys };
    // serialize
    std::ostringstream oss;
    binary_archive<true> ar(oss);
    bool r = ::do_serialize(ar, field);
    CHECK_AND_NO_ASSERT_MES_L1(r, false, "failed to serialize tx extra additional tx pub keys");
    // append
    std::string tx_extra_str = oss.str();
    size_t pos = tx_extra.size();
    tx_extra.resize(tx_extra.size() + tx_extra_str.size());
    memcpy(&tx_extra[pos], tx_extra_str.data(), tx_extra_str.size());
    return true;
  }
  //---------------------------------------------------------------
  bool add_extra_nonce_to_tx_extra(std::vector<uint8_t>& tx_extra, const blobdata& extra_nonce)
  {
    CHECK_AND_ASSERT_MES(extra_nonce.size() <= TX_EXTRA_NONCE_MAX_COUNT, false, "extra nonce could be 255 bytes max");
    size_t start_pos = tx_extra.size();
    tx_extra.resize(tx_extra.size() + 2 + extra_nonce.size());
    //write tag
    tx_extra[start_pos] = TX_EXTRA_NONCE;
    //write len
    ++start_pos;
    tx_extra[start_pos] = static_cast<uint8_t>(extra_nonce.size());
    //write data
    ++start_pos;
    memcpy(&tx_extra[start_pos], extra_nonce.data(), extra_nonce.size());
    return true;
  }
  //---------------------------------------------------------------
  bool remove_field_from_tx_extra(std::vector<uint8_t>& tx_extra, const std::type_info &type)
  {
    if (tx_extra.empty())
      return true;
    std::string extra_str(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size());
    std::istringstream iss(extra_str);
    binary_archive<false> ar(iss);
    std::ostringstream oss;
    binary_archive<true> newar(oss);

    bool eof = false;
    while (!eof)
    {
      tx_extra_field field;
      bool r = ::do_serialize(ar, field);
      CHECK_AND_NO_ASSERT_MES_L1(r, false, "failed to deserialize extra field. extra = " << string_tools::buff_to_hex_nodelimer(std::string(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size())));
      if (field.type() != type)
        ::do_serialize(newar, field);

      std::ios_base::iostate state = iss.rdstate();
      eof = (EOF == iss.peek());
      iss.clear(state);
    }
    CHECK_AND_NO_ASSERT_MES_L1(::serialization::check_stream_state(ar), false, "failed to deserialize extra field. extra = " << string_tools::buff_to_hex_nodelimer(std::string(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size())));
    tx_extra.clear();
    std::string s = oss.str();
    tx_extra.reserve(s.size());
    std::copy(s.begin(), s.end(), std::back_inserter(tx_extra));
    return true;
  }
  //---------------------------------------------------------------
  void set_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash& payment_id)
  {
    extra_nonce.clear();
    extra_nonce.push_back(TX_EXTRA_NONCE_PAYMENT_ID);
    const uint8_t* payment_id_ptr = reinterpret_cast<const uint8_t*>(&payment_id);
    std::copy(payment_id_ptr, payment_id_ptr + sizeof(payment_id), std::back_inserter(extra_nonce));
  }
  //---------------------------------------------------------------
  void set_encrypted_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash8& payment_id)
  {
    extra_nonce.clear();
    extra_nonce.push_back(TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID);
    const uint8_t* payment_id_ptr = reinterpret_cast<const uint8_t*>(&payment_id);
    std::copy(payment_id_ptr, payment_id_ptr + sizeof(payment_id), std::back_inserter(extra_nonce));
  }
  //---------------------------------------------------------------
  bool get_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash& payment_id)
  {
    if(sizeof(crypto::hash) + 1 != extra_nonce.size())
      return false;
    if(TX_EXTRA_NONCE_PAYMENT_ID != extra_nonce[0])
      return false;
    payment_id = *reinterpret_cast<const crypto::hash*>(extra_nonce.data() + 1);
    return true;
  }
  //---------------------------------------------------------------
  bool get_encrypted_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash8& payment_id)
  {
    if(sizeof(crypto::hash8) + 1 != extra_nonce.size())
      return false;
    if (TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID != extra_nonce[0])
      return false;
    payment_id = *reinterpret_cast<const crypto::hash8*>(extra_nonce.data() + 1);
    return true;
  }
  //---------------------------------------------------------------
  bool encrypt_payment_id(crypto::hash8 &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key)
  {
    crypto::key_derivation derivation;
    crypto::hash hash;
    char data[33]; /* A hash, and an extra byte */

    if (!generate_key_derivation(public_key, secret_key, derivation))
      return false;

    memcpy(data, &derivation, 32);
    data[32] = ENCRYPTED_PAYMENT_ID_TAIL;
    cn_fast_hash(data, 33, hash);

    for (size_t b = 0; b < 8; ++b)
      payment_id.data[b] ^= hash.data[b];

    return true;
  }
  bool decrypt_payment_id(crypto::hash8 &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key)
  {
    // Encryption and decryption are the same operation (xor with a key)
    return encrypt_payment_id(payment_id, public_key, secret_key);
  }
  //---------------------------------------------------------------
  bool get_inputs_money_amount(const transaction& tx, uint64_t& money)
  {
    money = 0;
    for(const auto& in: tx.vin)
    {
      CHECKED_GET_SPECIFIC_VARIANT(in, const txin_to_key, tokey_in, false);
      money += tokey_in.amount;
    }
    return true;
  }
  //---------------------------------------------------------------
  uint64_t get_block_height(const block& b)
  {
    CHECK_AND_ASSERT_MES(b.miner_tx.vin.size() == 1, 0, "wrong miner tx in block: " << get_block_hash(b) << ", b.miner_tx.vin.size() != 1");
    CHECKED_GET_SPECIFIC_VARIANT(b.miner_tx.vin[0], const txin_gen, coinbase_in, 0);
    return coinbase_in.height;
  }
  //---------------------------------------------------------------
  bool check_inputs_types_supported(const transaction& tx)
  {
    for(const auto& in: tx.vin)
    {
      CHECK_AND_ASSERT_MES(in.type() == typeid(txin_to_key), false, "wrong variant type: "
        << in.type().name() << ", expected " << typeid(txin_to_key).name()
        << ", in transaction id=" << get_transaction_hash(tx));

    }
    return true;
  }
  //-----------------------------------------------------------------------------------------------
  bool check_outs_valid(const transaction& tx)
  {
    for(const tx_out& out: tx.vout)
    {
      CHECK_AND_ASSERT_MES(out.target.type() == typeid(txout_to_key), false, "wrong variant type: "
        << out.target.type().name() << ", expected " << typeid(txout_to_key).name()
        << ", in transaction id=" << get_transaction_hash(tx));

      if (tx.version == 1)
      {
        CHECK_AND_NO_ASSERT_MES(0 < out.amount, false, "zero amount output in transaction id=" << get_transaction_hash(tx));
      }

      if(!check_key(boost::get<txout_to_key>(out.target).key))
        return false;
    }
    return true;
  }
  //-----------------------------------------------------------------------------------------------
  bool check_money_overflow(const transaction& tx)
  {
    return check_inputs_overflow(tx) && check_outs_overflow(tx);
  }
  //---------------------------------------------------------------
  bool check_inputs_overflow(const transaction& tx)
  {
    uint64_t money = 0;
    for(const auto& in: tx.vin)
    {
      CHECKED_GET_SPECIFIC_VARIANT(in, const txin_to_key, tokey_in, false);
      if(money > tokey_in.amount + money)
        return false;
      money += tokey_in.amount;
    }
    return true;
  }
  //---------------------------------------------------------------
  bool check_outs_overflow(const transaction& tx)
  {
    uint64_t money = 0;
    for(const auto& o: tx.vout)
    {
      if(money > o.amount + money)
        return false;
      money += o.amount;
    }
    return true;
  }
  //---------------------------------------------------------------
  uint64_t get_outs_money_amount(const transaction& tx)
  {
    uint64_t outputs_amount = 0;
    for(const auto& o: tx.vout)
      outputs_amount += o.amount;
    return outputs_amount;
  }
  //---------------------------------------------------------------
  std::string short_hash_str(const crypto::hash& h)
  {
    std::string res = string_tools::pod_to_hex(h);
    CHECK_AND_ASSERT_MES(res.size() == 64, res, "wrong hash256 with string_tools::pod_to_hex conversion");
    auto erased_pos = res.erase(8, 48);
    res.insert(8, "....");
    return res;
  }
  //---------------------------------------------------------------
  bool is_out_to_acc(const account_keys& acc, const txout_to_key& out_key, const crypto::public_key& tx_pub_key, const std::vector<crypto::public_key>& additional_tx_pub_keys, size_t output_index)
  {
    crypto::key_derivation derivation;
    generate_key_derivation(tx_pub_key, acc.m_view_secret_key, derivation);
    crypto::public_key pk;
    derive_public_key(derivation, output_index, acc.m_account_address.m_spend_public_key, pk);
    if (pk == out_key.key)
      return true;
    // try additional tx pubkeys if available
    if (!additional_tx_pub_keys.empty())
    {
      CHECK_AND_ASSERT_MES(output_index < additional_tx_pub_keys.size(), false, "wrong number of additional tx pubkeys");
      generate_key_derivation(additional_tx_pub_keys[output_index], acc.m_view_secret_key, derivation);
      derive_public_key(derivation, output_index, acc.m_account_address.m_spend_public_key, pk);
      return pk == out_key.key;
    }
    return false;
  }
  //---------------------------------------------------------------
  boost::optional<subaddress_receive_info> is_out_to_acc_precomp(const std::unordered_map<crypto::public_key, subaddress_index>& subaddresses, const crypto::public_key& out_key, const crypto::key_derivation& derivation, const std::vector<crypto::key_derivation>& additional_derivations, size_t output_index)
  {
    // try the shared tx pubkey
    crypto::public_key subaddress_spendkey;
    derive_subaddress_public_key(out_key, derivation, output_index, subaddress_spendkey);
    auto found = subaddresses.find(subaddress_spendkey);
    if (found != subaddresses.end())
      return subaddress_receive_info{ found->second, derivation };
    // try additional tx pubkeys if available
    if (!additional_derivations.empty())
    {
      CHECK_AND_ASSERT_MES(output_index < additional_derivations.size(), boost::none, "wrong number of additional derivations");
      derive_subaddress_public_key(out_key, additional_derivations[output_index], output_index, subaddress_spendkey);
      found = subaddresses.find(subaddress_spendkey);
      if (found != subaddresses.end())
        return subaddress_receive_info{ found->second, additional_derivations[output_index] };
    }
    return boost::none;
  }
  //---------------------------------------------------------------
  bool lookup_acc_outs(const account_keys& acc, const transaction& tx, std::vector<size_t>& outs, uint64_t& money_transfered)
  {
    crypto::public_key tx_pub_key = get_tx_pub_key_from_extra(tx);
    if(null_pkey == tx_pub_key)
      return false;
    std::vector<crypto::public_key> additional_tx_pub_keys = get_additional_tx_pub_keys_from_extra(tx);
    return lookup_acc_outs(acc, tx, tx_pub_key, additional_tx_pub_keys, outs, money_transfered);
  }
  //---------------------------------------------------------------
  bool lookup_acc_outs(const account_keys& acc, const transaction& tx, const crypto::public_key& tx_pub_key, const std::vector<crypto::public_key>& additional_tx_pub_keys, std::vector<size_t>& outs, uint64_t& money_transfered)
  {
    CHECK_AND_ASSERT_MES(additional_tx_pub_keys.empty() || additional_tx_pub_keys.size() == tx.vout.size(), false, "wrong number of additional pubkeys" );
    money_transfered = 0;
    size_t i = 0;
    for(const tx_out& o:  tx.vout)
    {
      CHECK_AND_ASSERT_MES(o.target.type() ==  typeid(txout_to_key), false, "wrong type id in transaction out" );
      if(is_out_to_acc(acc, boost::get<txout_to_key>(o.target), tx_pub_key, additional_tx_pub_keys, i))
      {
        outs.push_back(i);
        money_transfered += o.amount;
      }
      i++;
    }
    return true;
  }
  //---------------------------------------------------------------
  void get_blob_hash(const blobdata& blob, crypto::hash& res)
  {
    cn_fast_hash(blob.data(), blob.size(), res);
  }
  //---------------------------------------------------------------
  void set_default_decimal_point(unsigned int decimal_point)
  {
    switch (decimal_point)
    {
      case 12:
      case 9:
      case 6:
      case 3:
      case 0:
        default_decimal_point = decimal_point;
        break;
      default:
        ASSERT_MES_AND_THROW("Invalid decimal point specification: " << decimal_point);
    }
  }
  //---------------------------------------------------------------
  unsigned int get_default_decimal_point()
  {
    return default_decimal_point;
  }
  //---------------------------------------------------------------
  std::string get_unit(unsigned int decimal_point)
  {
    if (decimal_point == (unsigned int)-1)
      decimal_point = default_decimal_point;
    switch (std::atomic_load(&default_decimal_point))
    {
      case 12:
        return "monero";
      case 9:
        return "millinero";
      case 6:
        return "micronero";
      case 3:
        return "nanonero";
      case 0:
        return "piconero";
      default:
        ASSERT_MES_AND_THROW("Invalid decimal point specification: " << default_decimal_point);
    }
  }
  //---------------------------------------------------------------
  std::string print_money(uint64_t amount, unsigned int decimal_point)
  {
    if (decimal_point == (unsigned int)-1)
      decimal_point = default_decimal_point;
    std::string s = std::to_string(amount);
    if(s.size() < decimal_point+1)
    {
      s.insert(0, decimal_point+1 - s.size(), '0');
    }
    if (decimal_point > 0)
      s.insert(s.size() - decimal_point, ".");
    return s;
  }
  //---------------------------------------------------------------
  crypto::hash get_blob_hash(const blobdata& blob)
  {
    crypto::hash h = null_hash;
    get_blob_hash(blob, h);
    return h;
  }
  //---------------------------------------------------------------
  crypto::hash get_transaction_hash(const transaction& t)
  {
    crypto::hash h = null_hash;
    get_transaction_hash(t, h, NULL);
    return h;
  }
  //---------------------------------------------------------------
  bool get_transaction_hash(const transaction& t, crypto::hash& res)
  {
    return get_transaction_hash(t, res, NULL);
  }
  //---------------------------------------------------------------
  bool calculate_transaction_hash(const transaction& t, crypto::hash& res, size_t* blob_size)
  {
    // v1 transactions hash the entire blob
    if (t.version == 1)
    {
      size_t ignored_blob_size, &blob_size_ref = blob_size ? *blob_size : ignored_blob_size;
      return get_object_hash(t, res, blob_size_ref);
    }

    // v2 transactions hash different parts together, than hash the set of those hashes
    crypto::hash hashes[3];

    // prefix
    get_transaction_prefix_hash(t, hashes[0]);

    transaction &tt = const_cast<transaction&>(t);

    // base rct
    {
      std::stringstream ss;
      binary_archive<true> ba(ss);
      const size_t inputs = t.vin.size();
      const size_t outputs = t.vout.size();
      bool r = tt.rct_signatures.serialize_rctsig_base(ba, inputs, outputs);
      CHECK_AND_ASSERT_MES(r, false, "Failed to serialize rct signatures base");
      cryptonote::get_blob_hash(ss.str(), hashes[1]);
    }

    // prunable rct
    if (t.rct_signatures.type == rct::RCTTypeNull)
    {
      hashes[2] = crypto::null_hash;
    }
    else
    {
      std::stringstream ss;
      binary_archive<true> ba(ss);
      const size_t inputs = t.vin.size();
      const size_t outputs = t.vout.size();
      const size_t mixin = t.vin.empty() ? 0 : t.vin[0].type() == typeid(txin_to_key) ? boost::get<txin_to_key>(t.vin[0]).key_offsets.size() - 1 : 0;
      bool r = tt.rct_signatures.p.serialize_rctsig_prunable(ba, t.rct_signatures.type, inputs, outputs, mixin);
      CHECK_AND_ASSERT_MES(r, false, "Failed to serialize rct signatures prunable");
      cryptonote::get_blob_hash(ss.str(), hashes[2]);
    }

    // the tx hash is the hash of the 3 hashes
    res = cn_fast_hash(hashes, sizeof(hashes));

    // we still need the size
    if (blob_size)
      *blob_size = get_object_blobsize(t);

    return true;
  }
  //---------------------------------------------------------------
  bool get_transaction_hash(const transaction& t, crypto::hash& res, size_t* blob_size)
  {
    if (t.is_hash_valid())
    {
#ifdef ENABLE_HASH_CASH_INTEGRITY_CHECK
      CHECK_AND_ASSERT_THROW_MES(!calculate_transaction_hash(t, res, blob_size) || t.hash == res, "tx hash cash integrity failure");
#endif
      res = t.hash;
      if (blob_size)
      {
        if (!t.is_blob_size_valid())
        {
          t.blob_size = get_object_blobsize(t);
          t.set_blob_size_valid(true);
        }
        *blob_size = t.blob_size;
      }
      ++tx_hashes_cached_count;
      return true;
    }
    ++tx_hashes_calculated_count;
    bool ret = calculate_transaction_hash(t, res, blob_size);
    if (!ret)
      return false;
    t.hash = res;
    t.set_hash_valid(true);
    if (blob_size)
    {
      t.blob_size = *blob_size;
      t.set_blob_size_valid(true);
    }
    return true;
  }
  //---------------------------------------------------------------
  bool get_transaction_hash(const transaction& t, crypto::hash& res, size_t& blob_size)
  {
    return get_transaction_hash(t, res, &blob_size);
  }
  //---------------------------------------------------------------
  blobdata get_block_hashing_blob(const block& b)
  {
    blobdata blob = t_serializable_object_to_blob(static_cast<block_header>(b));
    crypto::hash tree_root_hash = get_tx_tree_hash(b);
    blob.append(reinterpret_cast<const char*>(&tree_root_hash), sizeof(tree_root_hash));
    blob.append(tools::get_varint_data(b.tx_hashes.size()+1));
    return blob;
  }
  //---------------------------------------------------------------
  bool calculate_block_hash(const block& b, crypto::hash& res)
  {
    // EXCEPTION FOR BLOCK 202612
    const std::string correct_blob_hash_202612 = "3a8a2b3a29b50fc86ff73dd087ea43c6f0d6b8f936c849194d5c84c737903966";
    const std::string existing_block_id_202612 = "bbd604d2ba11ba27935e006ed39c9bfdd99b76bf4a50654bc1e1e61217962698";
    crypto::hash block_blob_hash = get_blob_hash(block_to_blob(b));

    if (string_tools::pod_to_hex(block_blob_hash) == correct_blob_hash_202612)
    {
      string_tools::hex_to_pod(existing_block_id_202612, res);
      return true;
    }
    bool hash_result = get_object_hash(get_block_hashing_blob(b), res);

    if (hash_result)
    {
      // make sure that we aren't looking at a block with the 202612 block id but not the correct blobdata
      if (string_tools::pod_to_hex(res) == existing_block_id_202612)
      {
        LOG_ERROR("Block with block id for 202612 but incorrect block blob hash found!");
        res = null_hash;
        return false;
      }
    }
    return hash_result;
  }
  //---------------------------------------------------------------
  bool get_block_hash(const block& b, crypto::hash& res)
  {
    if (b.is_hash_valid())
    {
#ifdef ENABLE_HASH_CASH_INTEGRITY_CHECK
      CHECK_AND_ASSERT_THROW_MES(!calculate_block_hash(b, res) || b.hash == res, "block hash cash integrity failure");
#endif
      res = b.hash;
      ++block_hashes_cached_count;
      return true;
    }
    ++block_hashes_calculated_count;
    bool ret = calculate_block_hash(b, res);
    if (!ret)
      return false;
    b.hash = res;
    b.set_hash_valid(true);
    return true;
  }
  //---------------------------------------------------------------
  crypto::hash get_block_hash(const block& b)
  {
    crypto::hash p = null_hash;
    get_block_hash(b, p);
    return p;
  }
  //---------------------------------------------------------------
  bool get_block_longhash(const block& b, crypto::hash& res, uint64_t height)
  {
    // block 202612 bug workaround
    const std::string longhash_202612 = "84f64766475d51837ac9efbef1926486e58563c95a19fef4aec3254f03000000";
    if (height == 202612)
    {
      string_tools::hex_to_pod(longhash_202612, res);
      return true;
    }
    blobdata bd = get_block_hashing_blob(b);
    crypto::cn_slow_hash(bd.data(), bd.size(), res);
    return true;
  }
  //---------------------------------------------------------------
  std::vector<uint64_t> relative_output_offsets_to_absolute(const std::vector<uint64_t>& off)
  {
    std::vector<uint64_t> res = off;
    for(size_t i = 1; i < res.size(); i++)
      res[i] += res[i-1];
    return res;
  }
  //---------------------------------------------------------------
  std::vector<uint64_t> absolute_output_offsets_to_relative(const std::vector<uint64_t>& off)
  {
    std::vector<uint64_t> res = off;
    if(!off.size())
      return res;
    std::sort(res.begin(), res.end());//just to be sure, actually it is already should be sorted
    for(size_t i = res.size()-1; i != 0; i--)
      res[i] -= res[i-1];

    return res;
  }
  //---------------------------------------------------------------
  crypto::hash get_block_longhash(const block& b, uint64_t height)
  {
    crypto::hash p = null_hash;
    get_block_longhash(b, p, height);
    return p;
  }
  //---------------------------------------------------------------
  bool parse_and_validate_block_from_blob(const blobdata& b_blob, block& b)
  {
    std::stringstream ss;
    ss << b_blob;
    binary_archive<false> ba(ss);
    bool r = ::serialization::serialize(ba, b);
    CHECK_AND_ASSERT_MES(r, false, "Failed to parse block from blob");
    b.invalidate_hashes();
    b.miner_tx.invalidate_hashes();
    return true;
  }
  //---------------------------------------------------------------
  blobdata block_to_blob(const block& b)
  {
    return t_serializable_object_to_blob(b);
  }
  //---------------------------------------------------------------
  bool block_to_blob(const block& b, blobdata& b_blob)
  {
    return t_serializable_object_to_blob(b, b_blob);
  }
  //---------------------------------------------------------------
  blobdata tx_to_blob(const transaction& tx)
  {
    return t_serializable_object_to_blob(tx);
  }
  //---------------------------------------------------------------
  bool tx_to_blob(const transaction& tx, blobdata& b_blob)
  {
    return t_serializable_object_to_blob(tx, b_blob);
  }
  //---------------------------------------------------------------
  void get_tx_tree_hash(const std::vector<crypto::hash>& tx_hashes, crypto::hash& h)
  {
    tree_hash(tx_hashes.data(), tx_hashes.size(), h);
  }
  //---------------------------------------------------------------
  crypto::hash get_tx_tree_hash(const std::vector<crypto::hash>& tx_hashes)
  {
    crypto::hash h = null_hash;
    get_tx_tree_hash(tx_hashes, h);
    return h;
  }
  //---------------------------------------------------------------
  crypto::hash get_tx_tree_hash(const block& b)
  {
    std::vector<crypto::hash> txs_ids;
    crypto::hash h = null_hash;
    size_t bl_sz = 0;
    get_transaction_hash(b.miner_tx, h, bl_sz);
    txs_ids.push_back(h);
    for(auto& th: b.tx_hashes)
      txs_ids.push_back(th);
    return get_tx_tree_hash(txs_ids);
  }
  //---------------------------------------------------------------
  bool is_valid_decomposed_amount(uint64_t amount)
  {
    const uint64_t *begin = valid_decomposed_outputs;
    const uint64_t *end = valid_decomposed_outputs + sizeof(valid_decomposed_outputs) / sizeof(valid_decomposed_outputs[0]);
    return std::binary_search(begin, end, amount);
  }
  //---------------------------------------------------------------
  void get_hash_stats(uint64_t &tx_hashes_calculated, uint64_t &tx_hashes_cached, uint64_t &block_hashes_calculated, uint64_t & block_hashes_cached)
  {
    tx_hashes_calculated = tx_hashes_calculated_count;
    tx_hashes_cached = tx_hashes_cached_count;
    block_hashes_calculated = block_hashes_calculated_count;
    block_hashes_cached = block_hashes_cached_count;
  }
  //---------------------------------------------------------------
  crypto::secret_key encrypt_key(crypto::secret_key key, const epee::wipeable_string &passphrase)
  {
    crypto::hash hash;
    crypto::cn_slow_hash(passphrase.data(), passphrase.size(), hash);
    sc_add((unsigned char*)key.data, (const unsigned char*)key.data, (const unsigned char*)hash.data);
    return key;
  }
  //---------------------------------------------------------------
  crypto::secret_key decrypt_key(crypto::secret_key key, const epee::wipeable_string &passphrase)
  {
    crypto::hash hash;
    crypto::cn_slow_hash(passphrase.data(), passphrase.size(), hash);
    sc_sub((unsigned char*)key.data, (const unsigned char*)key.data, (const unsigned char*)hash.data);
    return key;
  }

}