Merge pull request #6745

80e535c wallet2: adapt to deterministic unlock time (TheCharlatan)
4971219 blockchain: deterministic UNIX time unlock checks (moneromooo-monero)

13 files changed, 122 insertions, 51 deletions

diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index f50ab6a40..9bd1f44eb 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -180,6 +180,7 @@
 #define HF_VERSION_EFFECTIVE_SHORT_TERM_MEDIAN_IN_PENALTY 12
 #define HF_VERSION_EXACT_COINBASE               13
 #define HF_VERSION_CLSAG                        13
+#define HF_VERSION_DETERMINISTIC_UNLOCK_TIME    13
 
 #define PER_KB_FEE_QUANTIZATION_DECIMALS        8
 
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 82b82534b..93e3ef3bc 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -2267,8 +2267,9 @@ bool Blockchain::get_outs(const COMMAND_RPC_GET_OUTPUTS_BIN::request& req, COMMA
       MERROR("Unexpected output data size: expected " << req.outputs.size() << ", got " << data.size());
       return false;
     }
+    const uint8_t hf_version = m_hardfork->get_current_version();
     for (const auto &t: data)
-      res.outs.push_back({t.pubkey, t.commitment, is_tx_spendtime_unlocked(t.unlock_time), t.height, crypto::null_hash});
+      res.outs.push_back({t.pubkey, t.commitment, is_tx_spendtime_unlocked(t.unlock_time, hf_version), t.height, crypto::null_hash});
 
     if (req.get_txid)
     {
@@ -2292,7 +2293,8 @@ void Blockchain::get_output_key_mask_unlocked(const uint64_t& amount, const uint
   key = o_data.pubkey;
   mask = o_data.commitment;
   tx_out_index toi = m_db->get_output_tx_and_index(amount, index);
-  unlocked = is_tx_spendtime_unlocked(m_db->get_tx_unlock_time(toi.first));
+  const uint8_t hf_version = m_hardfork->get_current_version();
+  unlocked = is_tx_spendtime_unlocked(m_db->get_tx_unlock_time(toi.first), hf_version);
 }
 //------------------------------------------------------------------
 bool Blockchain::get_output_distribution(uint64_t amount, uint64_t from_height, uint64_t to_height, uint64_t &start_height, std::vector<uint64_t> &distribution, uint64_t &base) const
@@ -3363,7 +3365,7 @@ bool Blockchain::check_tx_inputs(transaction& tx, tx_verification_context &tvc,
 
     // make sure that output being spent matches up correctly with the
     // signature spending it.
-    if (!check_tx_input(tx.version, in_to_key, tx_prefix_hash, tx.version == 1 ? tx.signatures[sig_index] : std::vector<crypto::signature>(), tx.rct_signatures, pubkeys[sig_index], pmax_used_block_height))
+    if (!check_tx_input(tx.version, in_to_key, tx_prefix_hash, tx.version == 1 ? tx.signatures[sig_index] : std::vector<crypto::signature>(), tx.rct_signatures, pubkeys[sig_index], pmax_used_block_height, hf_version))
     {
       MERROR_VER("Failed to check ring signature for tx " << get_transaction_hash(tx) << "  vin key with k_image: " << in_to_key.k_image << "  sig_index: " << sig_index);
       if (pmax_used_block_height) // a default value of NULL is used when called from Blockchain::handle_block_to_main_chain()
@@ -3756,7 +3758,7 @@ uint64_t Blockchain::get_dynamic_base_fee_estimate(uint64_t grace_blocks) const
 //------------------------------------------------------------------
 // This function checks to see if a tx is unlocked.  unlock_time is either
 // a block index or a unix time.
-bool Blockchain::is_tx_spendtime_unlocked(uint64_t unlock_time) const
+bool Blockchain::is_tx_spendtime_unlocked(uint64_t unlock_time, uint8_t hf_version) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
   if(unlock_time < CRYPTONOTE_MAX_BLOCK_NUMBER)
@@ -3771,7 +3773,7 @@ bool Blockchain::is_tx_spendtime_unlocked(uint64_t unlock_time) const
   else
   {
     //interpret as time
-    uint64_t current_time = static_cast<uint64_t>(time(NULL));
+    const uint64_t current_time = hf_version >= HF_VERSION_DETERMINISTIC_UNLOCK_TIME ? get_adjusted_time(m_db->height()) : static_cast<uint64_t>(time(NULL));
     if(current_time + (get_current_hard_fork_version() < 2 ? CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1 : CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2) >= unlock_time)
       return true;
     else
@@ -3783,7 +3785,7 @@ bool Blockchain::is_tx_spendtime_unlocked(uint64_t unlock_time) const
 // This function locates all outputs associated with a given input (mixins)
 // and validates that they exist and are usable.  It also checks the ring
 // signature for each input.
-bool Blockchain::check_tx_input(size_t tx_version, const txin_to_key& txin, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig, const rct::rctSig &rct_signatures, std::vector<rct::ctkey> &output_keys, uint64_t* pmax_related_block_height) const
+bool Blockchain::check_tx_input(size_t tx_version, const txin_to_key& txin, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig, const rct::rctSig &rct_signatures, std::vector<rct::ctkey> &output_keys, uint64_t* pmax_related_block_height, uint8_t hf_version) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
 
@@ -3795,14 +3797,15 @@ bool Blockchain::check_tx_input(size_t tx_version, const txin_to_key& txin, cons
   {
     std::vector<rct::ctkey >& m_output_keys;
     const Blockchain& m_bch;
-    outputs_visitor(std::vector<rct::ctkey>& output_keys, const Blockchain& bch) :
-      m_output_keys(output_keys), m_bch(bch)
+    const uint8_t hf_version;
+    outputs_visitor(std::vector<rct::ctkey>& output_keys, const Blockchain& bch, uint8_t hf_version) :
+      m_output_keys(output_keys), m_bch(bch), hf_version(hf_version)
     {
     }
     bool handle_output(uint64_t unlock_time, const crypto::public_key &pubkey, const rct::key &commitment)
     {
       //check tx unlock time
-      if (!m_bch.is_tx_spendtime_unlocked(unlock_time))
+      if (!m_bch.is_tx_spendtime_unlocked(unlock_time, hf_version))
       {
         MERROR_VER("One of outputs for one of inputs has wrong tx.unlock_time = " << unlock_time);
         return false;
@@ -3821,7 +3824,7 @@ bool Blockchain::check_tx_input(size_t tx_version, const txin_to_key& txin, cons
   output_keys.clear();
 
   // collect output keys
-  outputs_visitor vi(output_keys, *this);
+  outputs_visitor vi(output_keys, *this, hf_version);
   if (!scan_outputkeys_for_indexes(tx_version, txin, vi, tx_prefix_hash, pmax_related_block_height))
   {
     MERROR_VER("Failed to get output keys for tx with amount = " << print_money(txin.amount) << " and count indexes " << txin.key_offsets.size());
@@ -3840,12 +3843,38 @@ bool Blockchain::check_tx_input(size_t tx_version, const txin_to_key& txin, cons
   return true;
 }
 //------------------------------------------------------------------
-//TODO: Is this intended to do something else?  Need to look into the todo there.
-uint64_t Blockchain::get_adjusted_time() const
+// only works on the main chain
+uint64_t Blockchain::get_adjusted_time(uint64_t height) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
-  //TODO: add collecting median time
-  return time(NULL);
+
+  // if not enough blocks, no proper median yet, return current time
+  if(height < BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW)
+  {
+      return static_cast<uint64_t>(time(NULL));
+  }
+  std::vector<uint64_t> timestamps;
+
+  // need most recent 60 blocks, get index of first of those
+  size_t offset = height - BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW;
+  timestamps.reserve(height - offset);
+  for(;offset < height; ++offset)
+  {
+    timestamps.push_back(m_db->get_block_timestamp(offset));
+  }
+  uint64_t median_ts = epee::misc_utils::median(timestamps);
+
+  // project the median to match approximately when the block being validated will appear
+  // the median is calculated from a chunk of past blocks, so we use +1 to offset onto the current block
+  median_ts += (BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW + 1) * DIFFICULTY_TARGET_V2 / 2;
+
+  // project the current block's time based on the previous block's time
+  // we don't use the current block's time directly to mitigate timestamp manipulation
+  uint64_t adjusted_current_block_ts = timestamps.back() + DIFFICULTY_TARGET_V2;
+
+  // return minimum of ~current block time and adjusted median time
+  // we do this since it's better to report a time in the past than a time in the future
+  return (adjusted_current_block_ts < median_ts ? adjusted_current_block_ts : median_ts);
 }
 //------------------------------------------------------------------
 //TODO: revisit, has changed a bit on upstream
@@ -3873,9 +3902,9 @@ bool Blockchain::check_block_timestamp(std::vector<uint64_t>& timestamps, const
 bool Blockchain::check_block_timestamp(const block& b, uint64_t& median_ts) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
-  if(b.timestamp > get_adjusted_time() + CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT)
+  if(b.timestamp > (uint64_t)time(NULL) + CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT)
   {
-    MERROR_VER("Timestamp of block with id: " << get_block_hash(b) << ", " << b.timestamp << ", bigger than adjusted time + 2 hours");
+    MERROR_VER("Timestamp of block with id: " << get_block_hash(b) << ", " << b.timestamp << ", bigger than local time + 2 hours");
     return false;
   }
 
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 20bd3e5d3..a9b7ca1da 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -1042,6 +1042,21 @@ namespace cryptonote
      */
     void flush_invalid_blocks();
 
+    /**
+     * @brief get the "adjusted time"
+     *
+     * Computes the median timestamp of the previous 60 blocks, projects it
+     * onto the current block to get an 'adjusted median time' which approximates
+     * what the current block's timestamp should be. Also projects the previous
+     * block's timestamp to estimate the current block's timestamp.
+     * 
+     * Returns the minimum of the two projections, or the current local time on
+     * the machine if less than 60 blocks are available.
+     *
+     * @return current time approximated from chain data
+     */
+    uint64_t get_adjusted_time(uint64_t height) const;
+
 #ifndef IN_UNIT_TESTS
   private:
 #endif
@@ -1182,10 +1197,11 @@ namespace cryptonote
      * @param output_keys return-by-reference the public keys of the outputs in the input set
      * @param rct_signatures the ringCT signatures, which are only valid if tx version > 1
      * @param pmax_related_block_height return-by-pointer the height of the most recent block in the input set
+     * @param hf_version the consensus rules version to use
      *
      * @return false if any output is not yet unlocked, or is missing, otherwise true
      */
-    bool check_tx_input(size_t tx_version,const txin_to_key& txin, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig, const rct::rctSig &rct_signatures, std::vector<rct::ctkey> &output_keys, uint64_t* pmax_related_block_height) const;
+    bool check_tx_input(size_t tx_version,const txin_to_key& txin, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig, const rct::rctSig &rct_signatures, std::vector<rct::ctkey> &output_keys, uint64_t* pmax_related_block_height, uint8_t hf_version) const;
 
     /**
      * @brief validate a transaction's inputs and their keys
@@ -1373,10 +1389,11 @@ namespace cryptonote
      * unlock_time is either a block index or a unix time.
      *
      * @param unlock_time the unlock parameter (height or time)
+     * @param hf_version the consensus rules version to use
      *
      * @return true if spendable, otherwise false
      */
-    bool is_tx_spendtime_unlocked(uint64_t unlock_time) const;
+    bool is_tx_spendtime_unlocked(uint64_t unlock_time, uint8_t hf_version) const;
 
     /**
      * @brief stores an invalid block in a separate container
@@ -1438,16 +1455,6 @@ namespace cryptonote
     bool check_block_timestamp(std::vector<uint64_t>& timestamps, const block& b) const { uint64_t median_ts; return check_block_timestamp(timestamps, b, median_ts); }
 
     /**
-     * @brief get the "adjusted time"
-     *
-     * Currently this simply returns the current time according to the
-     * user's machine.
-     *
-     * @return the current time
-     */
-    uint64_t get_adjusted_time() const;
-
-    /**
      * @brief finish an alternate chain's timestamp window from the main chain
      *
      * for an alternate chain, get the timestamps from the main chain to complete
diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index 74d0cf450..a50c70418 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -461,6 +461,8 @@ namespace cryptonote
         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.adjusted_time = m_core.get_blockchain_storage().get_adjusted_time(res.height);
+
     res.start_time = restricted ? 0 : (uint64_t)m_core.get_start_time();
     res.free_space = restricted ? std::numeric_limits<uint64_t>::max() : m_core.get_free_space();
     res.offline = m_core.offline();
diff --git a/src/rpc/core_rpc_server_commands_defs.h b/src/rpc/core_rpc_server_commands_defs.h
index 09cd67d7d..8748b0540 100644
--- a/src/rpc/core_rpc_server_commands_defs.h
+++ b/src/rpc/core_rpc_server_commands_defs.h
@@ -88,7 +88,7 @@ namespace cryptonote
 // advance which version they will stop working with
 // Don't go over 32767 for any of these
 #define CORE_RPC_VERSION_MAJOR 3
-#define CORE_RPC_VERSION_MINOR 1
+#define CORE_RPC_VERSION_MINOR 2
 #define MAKE_CORE_RPC_VERSION(major,minor) (((major)<<16)|(minor))
 #define CORE_RPC_VERSION MAKE_CORE_RPC_VERSION(CORE_RPC_VERSION_MAJOR, CORE_RPC_VERSION_MINOR)
 
@@ -675,6 +675,7 @@ namespace cryptonote
       uint64_t block_weight_limit;
       uint64_t block_size_median;
       uint64_t block_weight_median;
+      uint64_t adjusted_time;
       uint64_t start_time;
       uint64_t free_space;
       bool offline;
@@ -713,6 +714,7 @@ namespace cryptonote
         KV_SERIALIZE_OPT(block_weight_limit, (uint64_t)0)
         KV_SERIALIZE(block_size_median)
         KV_SERIALIZE_OPT(block_weight_median, (uint64_t)0)
+        KV_SERIALIZE(adjusted_time)
         KV_SERIALIZE(start_time)
         KV_SERIALIZE(free_space)
         KV_SERIALIZE(offline)
diff --git a/src/rpc/daemon_handler.cpp b/src/rpc/daemon_handler.cpp
index 248c54afb..e256322cb 100644
--- a/src/rpc/daemon_handler.cpp
+++ b/src/rpc/daemon_handler.cpp
@@ -538,6 +538,7 @@ namespace rpc
     res.info.cumulative_difficulty = (res.info.wide_cumulative_difficulty & 0xffffffffffffffff).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.adjusted_time = m_core.get_blockchain_storage().get_adjusted_time(res.info.height);
     res.info.start_time = (uint64_t)m_core.get_start_time();
     res.info.version = MONERO_VERSION;
 
diff --git a/src/rpc/message_data_structs.h b/src/rpc/message_data_structs.h
index 085148d8a..86424653f 100644
--- a/src/rpc/message_data_structs.h
+++ b/src/rpc/message_data_structs.h
@@ -196,6 +196,7 @@ namespace rpc
     uint64_t block_size_limit;
     uint64_t block_weight_limit;
     uint64_t block_size_median;
+    uint64_t adjusted_time;
     uint64_t block_weight_median;
     uint64_t start_time;
     std::string version;
diff --git a/src/serialization/json_object.cpp b/src/serialization/json_object.cpp
index 7c48cf6c3..67f042c2e 100644
--- a/src/serialization/json_object.cpp
+++ b/src/serialization/json_object.cpp
@@ -1342,6 +1342,7 @@ void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const cryptonote::r
   INSERT_INTO_JSON_OBJECT(dest, block_weight_limit, info.block_weight_limit);
   INSERT_INTO_JSON_OBJECT(dest, block_size_median, info.block_size_median);
   INSERT_INTO_JSON_OBJECT(dest, block_weight_median, info.block_weight_median);
+  INSERT_INTO_JSON_OBJECT(dest, adjusted_time, info.adjusted_time);
   INSERT_INTO_JSON_OBJECT(dest, start_time, info.start_time);
 
   dest.EndObject();
@@ -1375,6 +1376,7 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::rpc::DaemonInfo& inf
   GET_FROM_JSON_OBJECT(val, info.block_weight_limit, block_weight_limit);
   GET_FROM_JSON_OBJECT(val, info.block_size_median, block_size_median);
   GET_FROM_JSON_OBJECT(val, info.block_weight_median, block_weight_median);
+  GET_FROM_JSON_OBJECT(val, info.adjusted_time, adjusted_time);
   GET_FROM_JSON_OBJECT(val, info.start_time, start_time);
 }
 
diff --git a/src/simplewallet/simplewallet.cpp b/src/simplewallet/simplewallet.cpp
index f37d77933..5fb4131fa 100644
--- a/src/simplewallet/simplewallet.cpp
+++ b/src/simplewallet/simplewallet.cpp
@@ -8553,8 +8553,8 @@ bool simple_wallet::get_transfers(std::vector<std::string>& local_args, std::vec
         }
         else
         {
-          uint64_t current_time = static_cast<uint64_t>(time(NULL));
-          uint64_t threshold = current_time + (m_wallet->use_fork_rules(2, 0) ? CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2 : CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1);
+          const uint64_t adjusted_time = m_wallet->get_daemon_adjusted_time();
+          uint64_t threshold = adjusted_time + (m_wallet->use_fork_rules(2, 0) ? CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2 : CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1);
           if (threshold < pd.m_unlock_time)
             locked_msg = get_human_readable_timespan(std::chrono::seconds(pd.m_unlock_time - threshold));
         }
@@ -10265,8 +10265,8 @@ bool simple_wallet::show_transfer(const std::vector<std::string> &args)
       }
       else
       {
-        uint64_t current_time = static_cast<uint64_t>(time(NULL));
-        uint64_t threshold = current_time + (m_wallet->use_fork_rules(2, 0) ? CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2 : CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1);
+        const uint64_t adjusted_time = m_wallet->get_daemon_adjusted_time();
+        uint64_t threshold = adjusted_time + (m_wallet->use_fork_rules(2, 0) ? CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2 : CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1);
         if (threshold >= pd.m_unlock_time)
           success_msg_writer() << "unlocked for " << get_human_readable_timespan(std::chrono::seconds(threshold - pd.m_unlock_time));
         else
diff --git a/src/wallet/node_rpc_proxy.cpp b/src/wallet/node_rpc_proxy.cpp
index 95b8ce8bb..48a602bf3 100644
--- a/src/wallet/node_rpc_proxy.cpp
+++ b/src/wallet/node_rpc_proxy.cpp
@@ -72,6 +72,7 @@ void NodeRPCProxy::invalidate()
   m_rpc_version = 0;
   m_target_height = 0;
   m_block_weight_limit = 0;
+  m_adjusted_time = 0;
   m_get_info_time = 0;
   m_rpc_payment_info_time = 0;
   m_rpc_payment_seed_height = 0;
@@ -131,6 +132,7 @@ boost::optional<std::string> NodeRPCProxy::get_info()
     m_height = resp_t.height;
     m_target_height = resp_t.target_height;
     m_block_weight_limit = resp_t.block_weight_limit ? resp_t.block_weight_limit : resp_t.block_size_limit;
+    m_adjusted_time = resp_t.adjusted_time;
     m_get_info_time = now;
     m_height_time = now;
   }
@@ -171,6 +173,15 @@ boost::optional<std::string> NodeRPCProxy::get_block_weight_limit(uint64_t &bloc
   return boost::optional<std::string>();
 }
 
+boost::optional<std::string> NodeRPCProxy::get_adjusted_time(uint64_t &adjusted_time)
+{
+    auto res = get_info();
+    if (res)
+        return res;
+    adjusted_time = m_adjusted_time;
+    return boost::optional<std::string>();
+}
+
 boost::optional<std::string> NodeRPCProxy::get_earliest_height(uint8_t version, uint64_t &earliest_height)
 {
   if (m_offline)
diff --git a/src/wallet/node_rpc_proxy.h b/src/wallet/node_rpc_proxy.h
index 500ba81d4..51b7f01dd 100644
--- a/src/wallet/node_rpc_proxy.h
+++ b/src/wallet/node_rpc_proxy.h
@@ -52,6 +52,7 @@ public:
   void set_height(uint64_t h);
   boost::optional<std::string> get_target_height(uint64_t &height);
   boost::optional<std::string> get_block_weight_limit(uint64_t &block_weight_limit);
+  boost::optional<std::string> get_adjusted_time(uint64_t &adjusted_time);
   boost::optional<std::string> get_earliest_height(uint8_t version, uint64_t &earliest_height);
   boost::optional<std::string> get_dynamic_base_fee_estimate(uint64_t grace_blocks, uint64_t &fee);
   boost::optional<std::string> get_fee_quantization_mask(uint64_t &fee_quantization_mask);
@@ -84,6 +85,7 @@ private:
   uint64_t m_dynamic_base_fee_estimate_cached_height;
   uint64_t m_dynamic_base_fee_estimate_grace_blocks;
   uint64_t m_fee_quantization_mask;
+  uint64_t m_adjusted_time;
   uint32_t m_rpc_version;
   uint64_t m_target_height;
   uint64_t m_block_weight_limit;
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 26e3a5b14..e2a4d41c1 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -5969,7 +5969,7 @@ uint64_t wallet2::balance(uint32_t index_major, bool strict) const
   return amount;
 }
 //----------------------------------------------------------------------------------------------------
-uint64_t wallet2::unlocked_balance(uint32_t index_major, bool strict, uint64_t *blocks_to_unlock, uint64_t *time_to_unlock) const
+uint64_t wallet2::unlocked_balance(uint32_t index_major, bool strict, uint64_t *blocks_to_unlock, uint64_t *time_to_unlock)
 {
   uint64_t amount = 0;
   if (blocks_to_unlock)
@@ -6021,7 +6021,7 @@ std::map<uint32_t, uint64_t> wallet2::balance_per_subaddress(uint32_t index_majo
   return amount_per_subaddr;
 }
 //----------------------------------------------------------------------------------------------------
-std::map<uint32_t, std::pair<uint64_t, std::pair<uint64_t, uint64_t>>> wallet2::unlocked_balance_per_subaddress(uint32_t index_major, bool strict) const
+std::map<uint32_t, std::pair<uint64_t, std::pair<uint64_t, uint64_t>>> wallet2::unlocked_balance_per_subaddress(uint32_t index_major, bool strict)
 {
   std::map<uint32_t, std::pair<uint64_t, std::pair<uint64_t, uint64_t>>> amount_per_subaddr;
   const uint64_t blockchain_height = get_blockchain_current_height();
@@ -6069,7 +6069,7 @@ uint64_t wallet2::balance_all(bool strict) const
   return r;
 }
 //----------------------------------------------------------------------------------------------------
-uint64_t wallet2::unlocked_balance_all(bool strict, uint64_t *blocks_to_unlock, uint64_t *time_to_unlock) const
+uint64_t wallet2::unlocked_balance_all(bool strict, uint64_t *blocks_to_unlock, uint64_t *time_to_unlock)
 {
   uint64_t r = 0;
   if (blocks_to_unlock)
@@ -6234,12 +6234,12 @@ void wallet2::rescan_blockchain(bool hard, bool refresh, bool keep_key_images)
     finish_rescan_bc_keep_key_images(transfers_cnt, transfers_hash);
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::is_transfer_unlocked(const transfer_details& td) const
+bool wallet2::is_transfer_unlocked(const transfer_details& td)
 {
   return is_transfer_unlocked(td.m_tx.unlock_time, td.m_block_height);
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::is_transfer_unlocked(uint64_t unlock_time, uint64_t block_height) const
+bool wallet2::is_transfer_unlocked(uint64_t unlock_time, uint64_t block_height)
 {
   if(!is_tx_spendtime_unlocked(unlock_time, block_height))
     return false;
@@ -6250,7 +6250,7 @@ bool wallet2::is_transfer_unlocked(uint64_t unlock_time, uint64_t block_height)
   return true;
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::is_tx_spendtime_unlocked(uint64_t unlock_time, uint64_t block_height) const
+bool wallet2::is_tx_spendtime_unlocked(uint64_t unlock_time, uint64_t block_height)
 {
   if(unlock_time < CRYPTONOTE_MAX_BLOCK_NUMBER)
   {
@@ -6262,12 +6262,14 @@ bool wallet2::is_tx_spendtime_unlocked(uint64_t unlock_time, uint64_t block_heig
   }else
   {
     //interpret as time
-    uint64_t current_time = static_cast<uint64_t>(time(NULL));
+    uint64_t adjusted_time;
+    try { adjusted_time = get_daemon_adjusted_time(); }
+    catch(...) { adjusted_time = time(NULL); } // use local time if no daemon to report blockchain time
     // XXX: this needs to be fast, so we'd need to get the starting heights
     // from the daemon to be correct once voting kicks in
     uint64_t v2height = m_nettype == TESTNET ? 624634 : m_nettype == STAGENET ? 32000  : 1009827;
     uint64_t leeway = block_height < v2height ? CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V1 : CRYPTONOTE_LOCKED_TX_ALLOWED_DELTA_SECONDS_V2;
-    if(current_time + leeway >= unlock_time)
+    if(adjusted_time + leeway >= unlock_time)
       return true;
     else
       return false;
@@ -9109,7 +9111,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
   LOG_PRINT_L2("transfer_selected_rct done");
 }
 
-std::vector<size_t> wallet2::pick_preferred_rct_inputs(uint64_t needed_money, uint32_t subaddr_account, const std::set<uint32_t> &subaddr_indices) const
+std::vector<size_t> wallet2::pick_preferred_rct_inputs(uint64_t needed_money, uint32_t subaddr_account, const std::set<uint32_t> &subaddr_indices)
 {
   std::vector<size_t> picks;
   float current_output_relatdness = 1.0f;
@@ -10780,7 +10782,7 @@ uint64_t wallet2::get_upper_transaction_weight_limit()
     return full_reward_zone - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE;
 }
 //----------------------------------------------------------------------------------------------------
-std::vector<size_t> wallet2::select_available_outputs(const std::function<bool(const transfer_details &td)> &f) const
+std::vector<size_t> wallet2::select_available_outputs(const std::function<bool(const transfer_details &td)> &f)
 {
   std::vector<size_t> outputs;
   size_t n = 0;
@@ -12085,6 +12087,15 @@ uint64_t wallet2::get_daemon_blockchain_height(string &err)
   return height;
 }
 
+uint64_t wallet2::get_daemon_adjusted_time()
+{
+    uint64_t adjusted_time;
+
+    boost::optional<std::string> result = m_node_rpc_proxy.get_adjusted_time(adjusted_time);
+    THROW_WALLET_EXCEPTION_IF(result, error::wallet_internal_error, "Invalid adjusted time from daemon");
+    return adjusted_time;
+}
+
 uint64_t wallet2::get_daemon_blockchain_target_height(string &err)
 {
   err = "";
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index 7f80eaec1..eac99185c 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -939,13 +939,13 @@ private:
 
     // locked & unlocked balance of given or current subaddress account
     uint64_t balance(uint32_t subaddr_index_major, bool strict) const;
-    uint64_t unlocked_balance(uint32_t subaddr_index_major, bool strict, uint64_t *blocks_to_unlock = NULL, uint64_t *time_to_unlock = NULL) const;
+    uint64_t unlocked_balance(uint32_t subaddr_index_major, bool strict, uint64_t *blocks_to_unlock = NULL, uint64_t *time_to_unlock = NULL);
     // locked & unlocked balance per subaddress of given or current subaddress account
     std::map<uint32_t, uint64_t> balance_per_subaddress(uint32_t subaddr_index_major, bool strict) const;
-    std::map<uint32_t, std::pair<uint64_t, std::pair<uint64_t, uint64_t>>> unlocked_balance_per_subaddress(uint32_t subaddr_index_major, bool strict) const;
+    std::map<uint32_t, std::pair<uint64_t, std::pair<uint64_t, uint64_t>>> unlocked_balance_per_subaddress(uint32_t subaddr_index_major, bool strict);
     // all locked & unlocked balances of all subaddress accounts
     uint64_t balance_all(bool strict) const;
-    uint64_t unlocked_balance_all(bool strict, uint64_t *blocks_to_unlock = NULL, uint64_t *time_to_unlock = NULL) const;
+    uint64_t unlocked_balance_all(bool strict, uint64_t *blocks_to_unlock = NULL, uint64_t *time_to_unlock = NULL);
     template<typename T>
     void transfer_selected(const std::vector<cryptonote::tx_destination_entry>& dsts, const std::vector<size_t>& selected_transfers, size_t fake_outputs_count,
       std::vector<std::vector<tools::wallet2::get_outs_entry>> &outs,
@@ -1003,8 +1003,8 @@ private:
     uint64_t get_blockchain_current_height() const { return m_light_wallet_blockchain_height ? m_light_wallet_blockchain_height : m_blockchain.size(); }
     void rescan_spent();
     void rescan_blockchain(bool hard, bool refresh = true, bool keep_key_images = false);
-    bool is_transfer_unlocked(const transfer_details& td) const;
-    bool is_transfer_unlocked(uint64_t unlock_time, uint64_t block_height) const;
+    bool is_transfer_unlocked(const transfer_details& td);
+    bool is_transfer_unlocked(uint64_t unlock_time, uint64_t block_height);
 
     uint64_t get_last_block_reward() const { return m_last_block_reward; }
     uint64_t get_device_last_key_image_sync() const { return m_device_last_key_image_sync; }
@@ -1301,13 +1301,15 @@ private:
     const boost::optional<epee::net_utils::http::login>& get_daemon_login() const { return m_daemon_login; }
     uint64_t get_daemon_blockchain_height(std::string& err);
     uint64_t get_daemon_blockchain_target_height(std::string& err);
+    uint64_t get_daemon_adjusted_time();
+
    /*!
     * \brief Calculates the approximate blockchain height from current date/time.
     */
     uint64_t get_approximate_blockchain_height() const;
     uint64_t estimate_blockchain_height();
     std::vector<size_t> select_available_outputs_from_histogram(uint64_t count, bool atleast, bool unlocked, bool allow_rct);
-    std::vector<size_t> select_available_outputs(const std::function<bool(const transfer_details &td)> &f) const;
+    std::vector<size_t> select_available_outputs(const std::function<bool(const transfer_details &td)> &f);
     std::vector<size_t> select_available_unmixable_outputs();
     std::vector<size_t> select_available_mixable_outputs();
 
@@ -1536,7 +1538,7 @@ private:
 
     void set_tx_notify(const std::shared_ptr<tools::Notify> &notify) { m_tx_notify = notify; }
 
-    bool is_tx_spendtime_unlocked(uint64_t unlock_time, uint64_t block_height) const;
+    bool is_tx_spendtime_unlocked(uint64_t unlock_time, uint64_t block_height);
     void hash_m_transfer(const transfer_details & transfer, crypto::hash &hash) const;
     uint64_t hash_m_transfers(int64_t transfer_height, crypto::hash &hash) const;
     void finish_rescan_bc_keep_key_images(uint64_t transfer_height, const crypto::hash &hash);
@@ -1600,7 +1602,7 @@ private:
     std::vector<uint64_t> get_unspent_amounts_vector(bool strict);
     uint64_t get_dynamic_base_fee_estimate();
     float get_output_relatedness(const transfer_details &td0, const transfer_details &td1) const;
-    std::vector<size_t> pick_preferred_rct_inputs(uint64_t needed_money, uint32_t subaddr_account, const std::set<uint32_t> &subaddr_indices) const;
+    std::vector<size_t> pick_preferred_rct_inputs(uint64_t needed_money, uint32_t subaddr_account, const std::set<uint32_t> &subaddr_indices);
     void set_spent(size_t idx, uint64_t height);
     void set_unspent(size_t idx);
     bool is_spent(const transfer_details &td, bool strict = true) const;