Make difficulty 128 bit instead of 64 bit

Based on Boolberry work by:
  jahrsg <jahr@jahr.me>
  cr.zoidberg <crypto.zoidberg@gmail.com>

18 files changed, 456 insertions, 37 deletions

diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 3391d9bff..9f71fd068 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -54,7 +54,7 @@ using epee::string_tools::pod_to_hex;
 using namespace crypto;
 
 // Increase when the DB structure changes
-#define VERSION 4
+#define VERSION 5
 
 namespace
 {
@@ -274,7 +274,7 @@ typedef struct mdb_block_info_1
   uint64_t bi_timestamp;
   uint64_t bi_coins;
   uint64_t bi_weight; // a size_t really but we need 32-bit compat
-  difficulty_type bi_diff;
+  uint64_t bi_diff;
   crypto::hash bi_hash;
 } mdb_block_info_1;
 
@@ -284,7 +284,7 @@ typedef struct mdb_block_info_2
   uint64_t bi_timestamp;
   uint64_t bi_coins;
   uint64_t bi_weight; // a size_t really but we need 32-bit compat
-  difficulty_type bi_diff;
+  uint64_t bi_diff;
   crypto::hash bi_hash;
   uint64_t bi_cum_rct;
 } mdb_block_info_2;
@@ -295,13 +295,26 @@ typedef struct mdb_block_info_3
   uint64_t bi_timestamp;
   uint64_t bi_coins;
   uint64_t bi_weight; // a size_t really but we need 32-bit compat
-  difficulty_type bi_diff;
+  uint64_t bi_diff;
   crypto::hash bi_hash;
   uint64_t bi_cum_rct;
   uint64_t bi_long_term_block_weight;
 } mdb_block_info_3;
 
-typedef mdb_block_info_3 mdb_block_info;
+typedef struct mdb_block_info_4
+{
+  uint64_t bi_height;
+  uint64_t bi_timestamp;
+  uint64_t bi_coins;
+  uint64_t bi_weight; // a size_t really but we need 32-bit compat
+  uint64_t bi_diff_lo;
+  uint64_t bi_diff_hi;
+  crypto::hash bi_hash;
+  uint64_t bi_cum_rct;
+  uint64_t bi_long_term_block_weight;
+} mdb_block_info_4;
+
+typedef mdb_block_info_4 mdb_block_info;
 
 typedef struct blk_height {
     crypto::hash bh_hash;
@@ -757,7 +770,8 @@ void BlockchainLMDB::add_block(const block& blk, size_t block_weight, uint64_t l
   bi.bi_timestamp = blk.timestamp;
   bi.bi_coins = coins_generated;
   bi.bi_weight = block_weight;
-  bi.bi_diff = cumulative_difficulty;
+  bi.bi_diff_hi = (cumulative_difficulty >> 64).convert_to<uint64_t>();
+  bi.bi_diff_lo = (cumulative_difficulty << 64 >> 64).convert_to<uint64_t>();
   bi.bi_hash = blk_hash;
   bi.bi_cum_rct = num_rct_outs;
   if (blk.major_version >= 4)
@@ -2527,7 +2541,9 @@ difficulty_type BlockchainLMDB::get_block_cumulative_difficulty(const uint64_t&
     throw0(DB_ERROR("Error attempting to retrieve a cumulative difficulty from the db"));
 
   mdb_block_info *bi = (mdb_block_info *)result.mv_data;
-  difficulty_type ret = bi->bi_diff;
+  difficulty_type ret = bi->bi_diff_hi;
+  ret <<= 64;
+  ret |= bi->bi_diff_lo;
   TXN_POSTFIX_RDONLY();
   return ret;
 }
@@ -5040,6 +5056,133 @@ void BlockchainLMDB::migrate_3_4()
   txn.commit();
 }
 
+void BlockchainLMDB::migrate_4_5()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  uint64_t i;
+  int result;
+  mdb_txn_safe txn(false);
+  MDB_val k, v;
+  char *ptr;
+
+  MGINFO_YELLOW("Migrating blockchain from DB version 4 to 5 - this may take a while:");
+
+  do {
+    LOG_PRINT_L1("migrating block info:");
+
+    result = mdb_txn_begin(m_env, NULL, 0, txn);
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", result).c_str()));
+
+    MDB_stat db_stats;
+    if ((result = mdb_stat(txn, m_blocks, &db_stats)))
+      throw0(DB_ERROR(lmdb_error("Failed to query m_blocks: ", result).c_str()));
+    const uint64_t blockchain_height = db_stats.ms_entries;
+
+    /* the block_info table name is the same but the old version and new version
+     * have incompatible data. Create a new table. We want the name to be similar
+     * to the old name so that it will occupy the same location in the DB.
+     */
+    MDB_dbi o_block_info = m_block_info;
+    lmdb_db_open(txn, "block_infn", MDB_INTEGERKEY | MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED, m_block_info, "Failed to open db handle for block_infn");
+    mdb_set_dupsort(txn, m_block_info, compare_uint64);
+
+
+    MDB_cursor *c_blocks;
+    result = mdb_cursor_open(txn, m_blocks, &c_blocks);
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to open a cursor for blocks: ", result).c_str()));
+
+    MDB_cursor *c_old, *c_cur;
+    i = 0;
+    while(1) {
+      if (!(i % 1000)) {
+        if (i) {
+          LOGIF(el::Level::Info) {
+            std::cout << i << " / " << blockchain_height << "  \r" << std::flush;
+          }
+          txn.commit();
+          result = mdb_txn_begin(m_env, NULL, 0, txn);
+          if (result)
+            throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", result).c_str()));
+        }
+        result = mdb_cursor_open(txn, m_block_info, &c_cur);
+        if (result)
+          throw0(DB_ERROR(lmdb_error("Failed to open a cursor for block_infn: ", result).c_str()));
+        result = mdb_cursor_open(txn, o_block_info, &c_old);
+        if (result)
+          throw0(DB_ERROR(lmdb_error("Failed to open a cursor for block_info: ", result).c_str()));
+        if (!i) {
+          MDB_stat db_stat;
+          result = mdb_stat(txn, m_block_info, &db_stats);
+          if (result)
+            throw0(DB_ERROR(lmdb_error("Failed to query m_block_info: ", result).c_str()));
+          i = db_stats.ms_entries;
+        }
+      }
+      result = mdb_cursor_get(c_old, &k, &v, MDB_NEXT);
+      if (result == MDB_NOTFOUND) {
+        txn.commit();
+        break;
+      }
+      else if (result)
+        throw0(DB_ERROR(lmdb_error("Failed to get a record from block_info: ", result).c_str()));
+      const mdb_block_info_3 *bi_old = (const mdb_block_info_3*)v.mv_data;
+      mdb_block_info_4 bi;
+      bi.bi_height = bi_old->bi_height;
+      bi.bi_timestamp = bi_old->bi_timestamp;
+      bi.bi_coins = bi_old->bi_coins;
+      bi.bi_weight = bi_old->bi_weight;
+      bi.bi_diff_lo = bi_old->bi_diff;
+      bi.bi_diff_hi = 0;
+      bi.bi_hash = bi_old->bi_hash;
+      bi.bi_cum_rct = bi_old->bi_cum_rct;
+      bi.bi_long_term_block_weight = bi_old->bi_long_term_block_weight;
+
+      MDB_val_set(nv, bi);
+      result = mdb_cursor_put(c_cur, (MDB_val *)&zerokval, &nv, MDB_APPENDDUP);
+      if (result)
+        throw0(DB_ERROR(lmdb_error("Failed to put a record into block_infn: ", result).c_str()));
+      /* we delete the old records immediately, so the overall DB and mapsize should not grow.
+       * This is a little slower than just letting mdb_drop() delete it all at the end, but
+       * it saves a significant amount of disk space.
+       */
+      result = mdb_cursor_del(c_old, 0);
+      if (result)
+        throw0(DB_ERROR(lmdb_error("Failed to delete a record from block_info: ", result).c_str()));
+      i++;
+    }
+
+    result = mdb_txn_begin(m_env, NULL, 0, txn);
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", result).c_str()));
+    /* Delete the old table */
+    result = mdb_drop(txn, o_block_info, 1);
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to delete old block_info table: ", result).c_str()));
+
+    RENAME_DB("block_infn");
+    mdb_dbi_close(m_env, m_block_info);
+
+    lmdb_db_open(txn, "block_info", MDB_INTEGERKEY | MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED, m_block_info, "Failed to open db handle for block_infn");
+    mdb_set_dupsort(txn, m_block_info, compare_uint64);
+
+    txn.commit();
+  } while(0);
+
+  uint32_t version = 5;
+  v.mv_data = (void *)&version;
+  v.mv_size = sizeof(version);
+  MDB_val_str(vk, "version");
+  result = mdb_txn_begin(m_env, NULL, 0, txn);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", result).c_str()));
+  result = mdb_put(txn, m_properties, &vk, &v, 0);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Failed to update version for the db: ", result).c_str()));
+  txn.commit();
+}
+
 void BlockchainLMDB::migrate(const uint32_t oldversion)
 {
   if (oldversion < 1)
@@ -5050,6 +5193,8 @@ void BlockchainLMDB::migrate(const uint32_t oldversion)
     migrate_2_3();
   if (oldversion < 4)
     migrate_3_4();
+  if (oldversion < 5)
+    migrate_4_5();
 }
 
 }  // namespace cryptonote
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index 9185bd409..2f89b77ac 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -418,6 +418,9 @@ private:
   // migrate from DB version 3 to 4
   void migrate_3_4();
 
+  // migrate from DB version 4 to 5
+  void migrate_4_5();
+
   void cleanup_batch();
 
 private:
diff --git a/src/blockchain_utilities/blockchain_import.cpp b/src/blockchain_utilities/blockchain_import.cpp
index e4efdc3cb..8454595ac 100644
--- a/src/blockchain_utilities/blockchain_import.cpp
+++ b/src/blockchain_utilities/blockchain_import.cpp
@@ -294,7 +294,8 @@ int import_from_file(cryptonote::core& core, const std::string& import_file_path
   }
 
   // 4 byte magic + (currently) 1024 byte header structures
-  bootstrap.seek_to_first_chunk(import_file);
+  uint8_t major_version, minor_version;
+  bootstrap.seek_to_first_chunk(import_file, major_version, minor_version);
 
   std::string str1;
   char buffer1[1024];
@@ -415,7 +416,23 @@ int import_from_file(cryptonote::core& core, const std::string& import_file_path
     {
       str1.assign(buffer_block, chunk_size);
       bootstrap::block_package bp;
-      if (! ::serialization::parse_binary(str1, bp))
+      bool res;
+      if (major_version == 0)
+      {
+        bootstrap::block_package_1 bp1;
+        res = ::serialization::parse_binary(str1, bp1);
+        if (res)
+        {
+          bp.block = std::move(bp1.block);
+          bp.txs = std::move(bp1.txs);
+          bp.block_weight = bp1.block_weight;
+          bp.cumulative_difficulty = bp1.cumulative_difficulty;
+          bp.coins_generated = bp1.coins_generated;
+        }
+      }
+      else
+        res = ::serialization::parse_binary(str1, bp);
+      if (!res)
         throw std::runtime_error("Error in deserialization of chunk");
 
       int display_interval = 1000;
diff --git a/src/blockchain_utilities/bootstrap_file.cpp b/src/blockchain_utilities/bootstrap_file.cpp
index fb9a24f5d..252c79776 100644
--- a/src/blockchain_utilities/bootstrap_file.cpp
+++ b/src/blockchain_utilities/bootstrap_file.cpp
@@ -124,8 +124,8 @@ bool BootstrapFile::initialize_file()
   *m_raw_data_file << blob;
 
   bootstrap::file_info bfi;
-  bfi.major_version = 0;
-  bfi.minor_version = 1;
+  bfi.major_version = 1;
+  bfi.minor_version = 0;
   bfi.header_size = header_size;
 
   bootstrap::blocks_info bbi;
@@ -323,7 +323,7 @@ bool BootstrapFile::store_blockchain_raw(Blockchain* _blockchain_storage, tx_mem
   return BootstrapFile::close();
 }
 
-uint64_t BootstrapFile::seek_to_first_chunk(std::ifstream& import_file)
+uint64_t BootstrapFile::seek_to_first_chunk(std::ifstream& import_file, uint8_t &major_version, uint8_t &minor_version)
 {
   uint32_t file_magic;
 
@@ -371,6 +371,8 @@ uint64_t BootstrapFile::seek_to_first_chunk(std::ifstream& import_file)
   uint64_t full_header_size = sizeof(file_magic) + bfi.header_size;
   import_file.seekg(full_header_size);
 
+  major_version = bfi.major_version;
+  minor_version = bfi.minor_version;
   return full_header_size;
 }
 
@@ -461,7 +463,8 @@ uint64_t BootstrapFile::count_blocks(const std::string& import_file_path, std::s
   }
 
   uint64_t full_header_size; // 4 byte magic + length of header structures
-  full_header_size = seek_to_first_chunk(import_file);
+  uint8_t major_version, minor_version;
+  full_header_size = seek_to_first_chunk(import_file, major_version, minor_version);
 
   MINFO("Scanning blockchain from bootstrap file...");
   bool quit = false;
diff --git a/src/blockchain_utilities/bootstrap_file.h b/src/blockchain_utilities/bootstrap_file.h
index 5fb2cf366..1e6ef5d81 100644
--- a/src/blockchain_utilities/bootstrap_file.h
+++ b/src/blockchain_utilities/bootstrap_file.h
@@ -60,7 +60,7 @@ public:
   uint64_t count_bytes(std::ifstream& import_file, uint64_t blocks, uint64_t& h, bool& quit);
   uint64_t count_blocks(const std::string& dir_path, std::streampos& start_pos, uint64_t& seek_height);
   uint64_t count_blocks(const std::string& dir_path);
-  uint64_t seek_to_first_chunk(std::ifstream& import_file);
+  uint64_t seek_to_first_chunk(std::ifstream& import_file, uint8_t &major_version, uint8_t &minor_version);
 
   bool store_blockchain_raw(cryptonote::Blockchain* cs, cryptonote::tx_memory_pool* txp,
       boost::filesystem::path& output_file, uint64_t use_block_height=0);
diff --git a/src/blockchain_utilities/bootstrap_serialization.h b/src/blockchain_utilities/bootstrap_serialization.h
index 554c6d56e..70b3eea7e 100644
--- a/src/blockchain_utilities/bootstrap_serialization.h
+++ b/src/blockchain_utilities/bootstrap_serialization.h
@@ -29,7 +29,7 @@
 #pragma once
 
 #include "cryptonote_basic/cryptonote_boost_serialization.h"
-#include "cryptonote_basic/difficulty.h"
+#include "serialization/difficulty_type.h"
 
 
 namespace cryptonote
@@ -66,6 +66,23 @@ namespace cryptonote
       END_SERIALIZE()
     };
 
+    struct block_package_1
+    {
+      cryptonote::block block;
+      std::vector<transaction> txs;
+      size_t block_weight;
+      uint64_t cumulative_difficulty;
+      uint64_t coins_generated;
+
+      BEGIN_SERIALIZE()
+        FIELD(block)
+        FIELD(txs)
+        VARINT_FIELD(block_weight)
+        VARINT_FIELD(cumulative_difficulty)
+        VARINT_FIELD(coins_generated)
+      END_SERIALIZE()
+    };
+
     struct block_package
     {
       cryptonote::block block;
@@ -78,7 +95,7 @@ namespace cryptonote
         FIELD(block)
         FIELD(txs)
         VARINT_FIELD(block_weight)
-        VARINT_FIELD(cumulative_difficulty)
+        FIELD(cumulative_difficulty)
         VARINT_FIELD(coins_generated)
       END_SERIALIZE()
     };
diff --git a/src/cryptonote_basic/cryptonote_boost_serialization.h b/src/cryptonote_basic/cryptonote_boost_serialization.h
index 1840b6d2b..3dd98f0c6 100644
--- a/src/cryptonote_basic/cryptonote_boost_serialization.h
+++ b/src/cryptonote_basic/cryptonote_boost_serialization.h
@@ -40,6 +40,7 @@
 #include <boost/archive/portable_binary_iarchive.hpp>
 #include <boost/archive/portable_binary_oarchive.hpp>
 #include "cryptonote_basic.h"
+#include "difficulty.h"
 #include "common/unordered_containers_boost_serialization.h"
 #include "crypto/crypto.h"
 #include "ringct/rctTypes.h"
@@ -346,6 +347,34 @@ namespace boost
     a & x.range_proof_type;
     a & x.bp_version;
   }
+
+  template <class Archive>
+  inline void serialize(Archive &a, cryptonote::difficulty_type &x, const boost::serialization::version_type ver)
+  {
+    if (Archive::is_loading::value)
+    {
+      // load high part
+      uint64_t v = 0;
+      a & v;
+      x = v;
+      // load low part
+      x = x << 64;
+      a & v;
+      x += v;
+    }
+    else
+    {
+      // store high part
+      cryptonote::difficulty_type x_ = x >> 64;
+      uint64_t v = x_.convert_to<uint64_t>();
+      a & v;
+      // store low part
+      x_ = x << 64 >> 64;
+      v = x_.convert_to<uint64_t>();
+      a & v;
+    }
+  }
+
 }
 }
 
diff --git a/src/cryptonote_basic/difficulty.cpp b/src/cryptonote_basic/difficulty.cpp
index 89b748a83..5162e53e6 100644
--- a/src/cryptonote_basic/difficulty.cpp
+++ b/src/cryptonote_basic/difficulty.cpp
@@ -102,7 +102,7 @@ namespace cryptonote {
     return a + b < a || (c && a + b == (uint64_t) -1);
   }
 
-  bool check_hash(const crypto::hash &hash, difficulty_type difficulty) {
+  bool check_hash_64(const crypto::hash &hash, uint64_t difficulty) {
     uint64_t low, high, top, cur;
     // First check the highest word, this will most likely fail for a random hash.
     mul(swap64le(((const uint64_t *) &hash)[3]), difficulty, top, high);
@@ -119,7 +119,7 @@ namespace cryptonote {
     return !carry;
   }
 
-  difficulty_type next_difficulty(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, size_t target_seconds) {
+  uint64_t next_difficulty_64(std::vector<std::uint64_t> timestamps, std::vector<uint64_t> cumulative_difficulties, size_t target_seconds) {
 
     if(timestamps.size() > DIFFICULTY_WINDOW)
     {
@@ -150,7 +150,7 @@ namespace cryptonote {
     if (time_span == 0) {
       time_span = 1;
     }
-    difficulty_type total_work = cumulative_difficulties[cut_end - 1] - cumulative_difficulties[cut_begin];
+    uint64_t total_work = cumulative_difficulties[cut_end - 1] - cumulative_difficulties[cut_begin];
     assert(total_work > 0);
     uint64_t low, high;
     mul(total_work, target_seconds, low, high);
@@ -162,4 +162,81 @@ namespace cryptonote {
     return (low + time_span - 1) / time_span;
   }
 
+#if defined(_MSC_VER)
+#ifdef max
+#undef max
+#endif
+#endif
+
+  const difficulty_type max64bit(std::numeric_limits<std::uint64_t>::max());
+  const boost::multiprecision::uint256_t max128bit(std::numeric_limits<boost::multiprecision::uint128_t>::max());
+  const boost::multiprecision::uint512_t max256bit(std::numeric_limits<boost::multiprecision::uint256_t>::max());
+
+#define FORCE_FULL_128_BITS
+
+  bool check_hash_128(const crypto::hash &hash, difficulty_type difficulty) {
+#ifndef FORCE_FULL_128_BITS
+    // fast check
+    if (difficulty >= max64bit && ((const uint64_t *) &hash)[3] > 0)
+      return false;
+#endif
+    // usual slow check
+    boost::multiprecision::uint512_t hashVal = 0;
+#ifdef FORCE_FULL_128_BITS
+    for(int i = 0; i < 4; i++) { // highest word is zero
+#else
+    for(int i = 1; i < 4; i++) { // highest word is zero
+#endif
+      hashVal <<= 64;
+      hashVal |= swap64le(((const uint64_t *) &hash)[3 - i]);
+    }
+    return hashVal * difficulty <= max256bit;
+  }
+
+  bool check_hash(const crypto::hash &hash, difficulty_type difficulty) {
+    if (difficulty <= max64bit) // if can convert to small difficulty - do it
+      return check_hash_64(hash, difficulty.convert_to<std::uint64_t>());
+    else
+      return check_hash_128(hash, difficulty);
+  }
+
+  difficulty_type next_difficulty(std::vector<uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, size_t target_seconds) {
+    //cutoff DIFFICULTY_LAG
+    if(timestamps.size() > DIFFICULTY_WINDOW)
+    {
+      timestamps.resize(DIFFICULTY_WINDOW);
+      cumulative_difficulties.resize(DIFFICULTY_WINDOW);
+    }
+
+
+    size_t length = timestamps.size();
+    assert(length == cumulative_difficulties.size());
+    if (length <= 1) {
+      return 1;
+    }
+    static_assert(DIFFICULTY_WINDOW >= 2, "Window is too small");
+    assert(length <= DIFFICULTY_WINDOW);
+    sort(timestamps.begin(), timestamps.end());
+    size_t cut_begin, cut_end;
+    static_assert(2 * DIFFICULTY_CUT <= DIFFICULTY_WINDOW - 2, "Cut length is too large");
+    if (length <= DIFFICULTY_WINDOW - 2 * DIFFICULTY_CUT) {
+      cut_begin = 0;
+      cut_end = length;
+    } else {
+      cut_begin = (length - (DIFFICULTY_WINDOW - 2 * DIFFICULTY_CUT) + 1) / 2;
+      cut_end = cut_begin + (DIFFICULTY_WINDOW - 2 * DIFFICULTY_CUT);
+    }
+    assert(/*cut_begin >= 0 &&*/ cut_begin + 2 <= cut_end && cut_end <= length);
+    uint64_t time_span = timestamps[cut_end - 1] - timestamps[cut_begin];
+    if (time_span == 0) {
+      time_span = 1;
+    }
+    difficulty_type total_work = cumulative_difficulties[cut_end - 1] - cumulative_difficulties[cut_begin];
+    assert(total_work > 0);
+    boost::multiprecision::uint256_t res =  (boost::multiprecision::uint256_t(total_work) * target_seconds + time_span - 1) / time_span;
+    if(res > max128bit)
+      return 0; // to behave like previous implementation, may be better return max128bit?
+    return res.convert_to<difficulty_type>();
+  }
+
 }
diff --git a/src/cryptonote_basic/difficulty.h b/src/cryptonote_basic/difficulty.h
index 8da355b22..f7a9376fb 100644
--- a/src/cryptonote_basic/difficulty.h
+++ b/src/cryptonote_basic/difficulty.h
@@ -32,12 +32,13 @@
 
 #include <cstdint>
 #include <vector>
+#include <boost/multiprecision/cpp_int.hpp>
 
 #include "crypto/hash.h"
 
 namespace cryptonote
 {
-    typedef std::uint64_t difficulty_type;
+    typedef boost::multiprecision::uint128_t difficulty_type;
 
     /**
      * @brief checks if a hash fits the given difficulty
@@ -51,6 +52,10 @@ namespace cryptonote
      *
      * @return true if valid, else false
      */
+    bool check_hash_64(const crypto::hash &hash, uint64_t difficulty);
+    uint64_t next_difficulty_64(std::vector<std::uint64_t> timestamps, std::vector<uint64_t> cumulative_difficulties, size_t target_seconds);
+
+    bool check_hash_128(const crypto::hash &hash, difficulty_type difficulty);
     bool check_hash(const crypto::hash &hash, difficulty_type difficulty);
     difficulty_type next_difficulty(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, size_t target_seconds);
 }
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index f5bd9bbb5..c6c79ff6e 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -1997,7 +1997,7 @@ bool Blockchain::find_blockchain_supplement(const std::list<crypto::hash>& qbloc
   return true;
 }
 //------------------------------------------------------------------
-uint64_t Blockchain::block_difficulty(uint64_t i) const
+difficulty_type Blockchain::block_difficulty(uint64_t i) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
   // WARNING: this function does not take m_blockchain_lock, and thus should only call read only
@@ -2196,7 +2196,11 @@ bool Blockchain::find_blockchain_supplement(const std::list<crypto::hash>& qbloc
 
   bool result = find_blockchain_supplement(qblock_ids, resp.m_block_ids, resp.start_height, resp.total_height);
   if (result)
-    resp.cumulative_difficulty = m_db->get_block_cumulative_difficulty(resp.total_height - 1);
+  {
+    cryptonote::difficulty_type wide_cumulative_difficulty = m_db->get_block_cumulative_difficulty(resp.total_height - 1);
+    resp.cumulative_difficulty = (wide_cumulative_difficulty << 64 >> 64).convert_to<uint64_t>();
+    resp.cumulative_difficulty_top64 = (wide_cumulative_difficulty >> 64).convert_to<uint64_t>();
+  }
 
   return result;
 }
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 3b8169764..89d8e7572 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -653,7 +653,7 @@ namespace cryptonote
      *
      * @return the difficulty
      */
-    uint64_t block_difficulty(uint64_t i) const;
+    difficulty_type block_difficulty(uint64_t i) const;
 
     /**
      * @brief gets blocks based on a list of block hashes
diff --git a/src/cryptonote_protocol/cryptonote_protocol_defs.h b/src/cryptonote_protocol/cryptonote_protocol_defs.h
index d582e3e9c..3083a5b4c 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_defs.h
+++ b/src/cryptonote_protocol/cryptonote_protocol_defs.h
@@ -34,6 +34,7 @@
 #include "serialization/keyvalue_serialization.h"
 #include "cryptonote_basic/cryptonote_basic.h"
 #include "cryptonote_basic/blobdatatype.h"
+
 namespace cryptonote
 {
 
@@ -208,6 +209,7 @@ namespace cryptonote
   {
     uint64_t current_height;
     uint64_t cumulative_difficulty;
+    uint64_t cumulative_difficulty_top64;
     crypto::hash  top_id;
     uint8_t top_version;
     uint32_t pruning_seed;
@@ -215,6 +217,7 @@ namespace cryptonote
     BEGIN_KV_SERIALIZE_MAP()
       KV_SERIALIZE(current_height)
       KV_SERIALIZE(cumulative_difficulty)
+      KV_SERIALIZE(cumulative_difficulty_top64)
       KV_SERIALIZE_VAL_POD_AS_BLOB(top_id)
       KV_SERIALIZE_OPT(top_version, (uint8_t)0)
       KV_SERIALIZE_OPT(pruning_seed, (uint32_t)0)
@@ -245,12 +248,14 @@ namespace cryptonote
       uint64_t start_height;
       uint64_t total_height;
       uint64_t cumulative_difficulty;
+      uint64_t cumulative_difficulty_top64;
       std::vector<crypto::hash> m_block_ids;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(start_height)
         KV_SERIALIZE(total_height)
         KV_SERIALIZE(cumulative_difficulty)
+        KV_SERIALIZE(cumulative_difficulty_top64)
         KV_SERIALIZE_CONTAINER_POD_AS_BLOB(m_block_ids)
       END_KV_SERIALIZE_MAP()
     };
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index b33867e8b..32f0afceb 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -398,7 +398,9 @@ namespace cryptonote
   {
     m_core.get_blockchain_top(hshd.current_height, hshd.top_id);
     hshd.top_version = m_core.get_ideal_hard_fork_version(hshd.current_height);
-    hshd.cumulative_difficulty = m_core.get_block_cumulative_difficulty(hshd.current_height);
+    difficulty_type wide_cumulative_difficulty = m_core.get_block_cumulative_difficulty(hshd.current_height);
+    hshd.cumulative_difficulty = (wide_cumulative_difficulty << 64 >> 64).convert_to<uint64_t>();
+    hshd.cumulative_difficulty_top64 = (wide_cumulative_difficulty >> 64).convert_to<uint64_t>();
     hshd.current_height +=1;
     hshd.pruning_seed = m_core.get_blockchain_pruning_seed();
     return true;
diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index 56b0361a7..c5557b2e3 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -70,6 +70,13 @@ namespace
   {
     return (value + quantum - 1) / quantum * quantum;
   }
+
+  void store_difficulty(cryptonote::difficulty_type difficulty, uint64_t &sdiff, std::string &swdiff, uint64_t &stop64)
+  {
+    sdiff = (difficulty << 64 >> 64).convert_to<uint64_t>();
+    swdiff = difficulty.convert_to<std::string>();
+    stop64 = (difficulty >> 64).convert_to<uint64_t>();
+  }
 }
 
 namespace cryptonote
@@ -219,7 +226,7 @@ namespace cryptonote
     ++res.height; // turn top block height into blockchain height
     res.top_block_hash = string_tools::pod_to_hex(top_hash);
     res.target_height = m_core.get_target_blockchain_height();
-    res.difficulty = m_core.get_blockchain_storage().get_difficulty_for_next_block();
+    store_difficulty(m_core.get_blockchain_storage().get_difficulty_for_next_block(), res.difficulty, res.wide_difficulty, res.difficulty_top64);
     res.target = m_core.get_blockchain_storage().get_difficulty_target();
     res.tx_count = m_core.get_blockchain_storage().get_total_transactions() - res.height; //without coinbase
     res.tx_pool_size = m_core.get_pool_transactions_count();
@@ -236,7 +243,8 @@ namespace cryptonote
     res.testnet = net_type == TESTNET;
     res.stagenet = net_type == STAGENET;
     res.nettype = net_type == MAINNET ? "mainnet" : net_type == TESTNET ? "testnet" : net_type == STAGENET ? "stagenet" : "fakechain";
-    res.cumulative_difficulty = m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(res.height - 1);
+    store_difficulty(m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(res.height - 1),
+        res.cumulative_difficulty, res.wide_cumulative_difficulty, res.cumulative_difficulty_top64);
     res.block_size_limit = res.block_weight_limit = m_core.get_blockchain_storage().get_current_cumulative_block_weight_limit();
     res.block_size_median = res.block_weight_median = m_core.get_blockchain_storage().get_current_cumulative_block_weight_median();
     res.status = CORE_RPC_STATUS_OK;
@@ -1196,13 +1204,15 @@ namespace cryptonote
     block b;
     cryptonote::blobdata blob_reserve;
     blob_reserve.resize(req.reserve_size, 0);
-    if(!m_core.get_block_template(b, info.address, res.difficulty, res.height, res.expected_reward, blob_reserve))
+    cryptonote::difficulty_type wdiff;
+    if(!m_core.get_block_template(b, info.address, wdiff, res.height, res.expected_reward, blob_reserve))
     {
       error_resp.code = CORE_RPC_ERROR_CODE_INTERNAL_ERROR;
       error_resp.message = "Internal error: failed to create block template";
       LOG_ERROR("Failed to create block template");
       return false;
     }
+    store_difficulty(wdiff, res.difficulty, res.wide_difficulty, res.difficulty_top64);
     blobdata block_blob = t_serializable_object_to_blob(b);
     crypto::public_key tx_pub_key = cryptonote::get_tx_pub_key_from_extra(b.miner_tx);
     if(tx_pub_key == crypto::null_pkey)
@@ -1375,8 +1385,10 @@ namespace cryptonote
     response.height = height;
     response.depth = m_core.get_current_blockchain_height() - height - 1;
     response.hash = string_tools::pod_to_hex(hash);
-    response.difficulty = m_core.get_blockchain_storage().block_difficulty(height);
-    response.cumulative_difficulty = response.block_weight = m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(height);
+    store_difficulty(m_core.get_blockchain_storage().block_difficulty(height),
+        response.difficulty, response.wide_difficulty, response.difficulty_top64);
+    store_difficulty(m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(height),
+        response.cumulative_difficulty, response.wide_cumulative_difficulty, response.cumulative_difficulty_top64);
     response.reward = get_block_reward(blk);
     response.block_size = response.block_weight = m_core.get_blockchain_storage().get_db().get_block_weight(height);
     response.num_txes = blk.tx_hashes.size();
@@ -1707,7 +1719,8 @@ namespace cryptonote
     ++res.height; // turn top block height into blockchain height
     res.top_block_hash = string_tools::pod_to_hex(top_hash);
     res.target_height = m_core.get_target_blockchain_height();
-    res.difficulty = m_core.get_blockchain_storage().get_difficulty_for_next_block();
+    store_difficulty(m_core.get_blockchain_storage().get_difficulty_for_next_block(),
+        res.difficulty, res.wide_difficulty, res.difficulty_top64);
     res.target = m_core.get_blockchain_storage().get_current_hard_fork_version() < 2 ? DIFFICULTY_TARGET_V1 : DIFFICULTY_TARGET_V2;
     res.tx_count = m_core.get_blockchain_storage().get_total_transactions() - res.height; //without coinbase
     res.tx_pool_size = m_core.get_pool_transactions_count();
@@ -1725,7 +1738,8 @@ namespace cryptonote
     res.stagenet = net_type == STAGENET;
     res.nettype = net_type == MAINNET ? "mainnet" : net_type == TESTNET ? "testnet" : net_type == STAGENET ? "stagenet" : "fakechain";
 
-    res.cumulative_difficulty = m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(res.height - 1);
+    store_difficulty(m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(res.height - 1),
+        res.cumulative_difficulty, res.wide_cumulative_difficulty, res.cumulative_difficulty_top64);
     res.block_size_limit = res.block_weight_limit = m_core.get_blockchain_storage().get_current_cumulative_block_weight_limit();
     res.block_size_median = res.block_weight_median = m_core.get_blockchain_storage().get_current_cumulative_block_weight_median();
     res.status = CORE_RPC_STATUS_OK;
@@ -1947,7 +1961,9 @@ namespace cryptonote
       std::list<std::pair<Blockchain::block_extended_info, std::vector<crypto::hash>>> chains = m_core.get_blockchain_storage().get_alternative_chains();
       for (const auto &i: chains)
       {
-        res.chains.push_back(COMMAND_RPC_GET_ALTERNATE_CHAINS::chain_info{epee::string_tools::pod_to_hex(get_block_hash(i.first.bl)), i.first.height, i.second.size(), i.first.cumulative_difficulty, {}, std::string()});
+        difficulty_type wdiff = i.first.cumulative_difficulty;
+        res.chains.push_back(COMMAND_RPC_GET_ALTERNATE_CHAINS::chain_info{epee::string_tools::pod_to_hex(get_block_hash(i.first.bl)), i.first.height, i.second.size(), 0, "", 0, {}, std::string()});
+        store_difficulty(wdiff, res.chains.back().difficulty, res.chains.back().wide_difficulty, res.chains.back().difficulty_top64);
         res.chains.back().block_hashes.reserve(i.second.size());
         for (const crypto::hash &block_id: i.second)
           res.chains.back().block_hashes.push_back(epee::string_tools::pod_to_hex(block_id));
diff --git a/src/rpc/core_rpc_server_commands_defs.h b/src/rpc/core_rpc_server_commands_defs.h
index f65c7c8dd..02450ff51 100644
--- a/src/rpc/core_rpc_server_commands_defs.h
+++ b/src/rpc/core_rpc_server_commands_defs.h
@@ -943,6 +943,8 @@ namespace cryptonote
       uint64_t height;
       uint64_t target_height;
       uint64_t difficulty;
+      std::string wide_difficulty;
+      uint64_t difficulty_top64;
       uint64_t target;
       uint64_t tx_count;
       uint64_t tx_pool_size;
@@ -958,6 +960,8 @@ namespace cryptonote
       std::string nettype;
       std::string top_block_hash;
       uint64_t cumulative_difficulty;
+      std::string wide_cumulative_difficulty;
+      uint64_t cumulative_difficulty_top64;
       uint64_t block_size_limit;
       uint64_t block_weight_limit;
       uint64_t block_size_median;
@@ -978,6 +982,8 @@ namespace cryptonote
         KV_SERIALIZE(height)
         KV_SERIALIZE(target_height)
         KV_SERIALIZE(difficulty)
+        KV_SERIALIZE(wide_difficulty)
+        KV_SERIALIZE(difficulty_top64)
         KV_SERIALIZE(target)
         KV_SERIALIZE(tx_count)
         KV_SERIALIZE(tx_pool_size)
@@ -993,6 +999,8 @@ namespace cryptonote
         KV_SERIALIZE(nettype)
         KV_SERIALIZE(top_block_hash)
         KV_SERIALIZE(cumulative_difficulty)
+        KV_SERIALIZE(wide_cumulative_difficulty)
+        KV_SERIALIZE(cumulative_difficulty_top64)
         KV_SERIALIZE(block_size_limit)
         KV_SERIALIZE_OPT(block_weight_limit, (uint64_t)0)
         KV_SERIALIZE(block_size_median)
@@ -1149,6 +1157,8 @@ namespace cryptonote
     struct response_t
     {
       uint64_t difficulty;
+      std::string wide_difficulty;
+      uint64_t difficulty_top64;
       uint64_t height;
       uint64_t reserved_offset;
       uint64_t expected_reward;
@@ -1160,6 +1170,8 @@ namespace cryptonote
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(difficulty)
+        KV_SERIALIZE(wide_difficulty)
+        KV_SERIALIZE(difficulty_top64)
         KV_SERIALIZE(height)
         KV_SERIALIZE(reserved_offset)
         KV_SERIALIZE(expected_reward)
@@ -1226,8 +1238,12 @@ namespace cryptonote
       uint64_t height;
       uint64_t depth;
       std::string hash;
-      difficulty_type difficulty;
-      difficulty_type cumulative_difficulty;
+      uint64_t difficulty;
+      std::string wide_difficulty;
+      uint64_t difficulty_top64;
+      uint64_t cumulative_difficulty;
+      std::string wide_cumulative_difficulty;
+      uint64_t cumulative_difficulty_top64;
       uint64_t reward;
       uint64_t block_size;
       uint64_t block_weight;
@@ -1246,7 +1262,11 @@ namespace cryptonote
         KV_SERIALIZE(depth)
         KV_SERIALIZE(hash)
         KV_SERIALIZE(difficulty)
+        KV_SERIALIZE(wide_difficulty)
+        KV_SERIALIZE(difficulty_top64)
         KV_SERIALIZE(cumulative_difficulty)
+        KV_SERIALIZE(wide_cumulative_difficulty)
+        KV_SERIALIZE(cumulative_difficulty_top64)
         KV_SERIALIZE(reward)
         KV_SERIALIZE(block_size)
         KV_SERIALIZE_OPT(block_weight, (uint64_t)0)
@@ -2248,6 +2268,8 @@ namespace cryptonote
       uint64_t height;
       uint64_t length;
       uint64_t difficulty;
+      std::string wide_difficulty;
+      uint64_t difficulty_top64;
       std::vector<std::string> block_hashes;
       std::string main_chain_parent_block;
 
@@ -2256,6 +2278,8 @@ namespace cryptonote
         KV_SERIALIZE(height)
         KV_SERIALIZE(length)
         KV_SERIALIZE(difficulty)
+        KV_SERIALIZE(wide_difficulty)
+        KV_SERIALIZE(difficulty_top64)
         KV_SERIALIZE(block_hashes)
         KV_SERIALIZE(main_chain_parent_block)
       END_KV_SERIALIZE_MAP()
diff --git a/src/rpc/daemon_handler.cpp b/src/rpc/daemon_handler.cpp
index bde2339bc..540afe6b9 100644
--- a/src/rpc/daemon_handler.cpp
+++ b/src/rpc/daemon_handler.cpp
@@ -436,7 +436,8 @@ namespace rpc
 
     auto& chain = m_core.get_blockchain_storage();
 
-    res.info.difficulty = chain.get_difficulty_for_next_block();
+    res.info.wide_difficulty = chain.get_difficulty_for_next_block();
+    res.info.difficulty = (res.info.wide_difficulty << 64 >> 64).convert_to<uint64_t>();
 
     res.info.target = chain.get_difficulty_target();
 
@@ -457,7 +458,8 @@ namespace rpc
     res.info.mainnet = m_core.get_nettype() == MAINNET;
     res.info.testnet = m_core.get_nettype() == TESTNET;
     res.info.stagenet = m_core.get_nettype() == STAGENET;
-    res.info.cumulative_difficulty = m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(res.info.height - 1);
+    res.info.wide_cumulative_difficulty = m_core.get_blockchain_storage().get_db().get_block_cumulative_difficulty(res.info.height - 1);
+    res.info.cumulative_difficulty = (res.info.wide_cumulative_difficulty << 64 >> 64).convert_to<uint64_t>();
     res.info.block_size_limit = res.info.block_weight_limit = m_core.get_blockchain_storage().get_current_cumulative_block_weight_limit();
     res.info.block_size_median = res.info.block_weight_median = m_core.get_blockchain_storage().get_current_cumulative_block_weight_median();
     res.info.start_time = (uint64_t)m_core.get_start_time();
@@ -826,7 +828,8 @@ namespace rpc
       header.reward += out.amount;
     }
 
-    header.difficulty = m_core.get_blockchain_storage().block_difficulty(header.height);
+    header.wide_difficulty = m_core.get_blockchain_storage().block_difficulty(header.height);
+    header.difficulty = (header.wide_difficulty << 64 >> 64).convert_to<uint64_t>();
 
     return true;
   }
diff --git a/src/rpc/message_data_structs.h b/src/rpc/message_data_structs.h
index 26c5038f6..2a43811cf 100644
--- a/src/rpc/message_data_structs.h
+++ b/src/rpc/message_data_structs.h
@@ -30,6 +30,7 @@
 
 #include "crypto/hash.h"
 #include "cryptonote_basic/cryptonote_basic.h"
+#include "cryptonote_basic/difficulty.h"
 #include "ringct/rctSigs.h"
 #include "rpc/rpc_handler.h"
 
@@ -165,6 +166,7 @@ namespace rpc
     uint64_t height;
     uint64_t depth;
     crypto::hash hash;
+    cryptonote::difficulty_type wide_difficulty;
     uint64_t difficulty;
     uint64_t reward;
   };
@@ -173,6 +175,7 @@ namespace rpc
   {
     uint64_t height;
     uint64_t target_height;
+    cryptonote::difficulty_type wide_difficulty;
     uint64_t difficulty;
     uint64_t target;
     uint64_t tx_count;
@@ -187,6 +190,7 @@ namespace rpc
     bool stagenet;
     std::string nettype;
     crypto::hash top_block_hash;
+    cryptonote::difficulty_type wide_cumulative_difficulty;
     uint64_t cumulative_difficulty;
     uint64_t block_size_limit;
     uint64_t block_weight_limit;
diff --git a/src/serialization/difficulty_type.h b/src/serialization/difficulty_type.h
new file mode 100644
index 000000000..e32e24b78
--- /dev/null
+++ b/src/serialization/difficulty_type.h
@@ -0,0 +1,65 @@
+// Copyright (c) 2019, 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.
+
+#pragma once
+
+#include "cryptonote_basic/difficulty.h"
+#include "serialization.h"
+
+template<> struct is_basic_type<cryptonote::difficulty_type> { typedef boost::true_type type; };
+
+template <template <bool> class Archive>
+inline bool do_serialize(Archive<false>& ar, cryptonote::difficulty_type &diff)
+{
+  uint64_t hi, lo;
+  ar.serialize_varint(hi);
+  if (!ar.stream().good())
+    return false;
+  ar.serialize_varint(lo);
+  if (!ar.stream().good())
+    return false;
+  diff = hi;
+  diff <<= 64;
+  diff += lo;
+  return true;
+}
+
+template <template <bool> class Archive>
+inline bool do_serialize(Archive<true>& ar, cryptonote::difficulty_type &diff)
+{
+  if (!ar.stream().good())
+    return false;
+  const uint64_t hi = (diff >> 64).convert_to<uint64_t>();
+  const uint64_t lo = (diff << 64 >> 64).convert_to<uint64_t>();
+  ar.serialize_varint(hi);
+  ar.serialize_varint(lo);
+  if (!ar.stream().good())
+    return false;
+  return true;
+}
+