miner block header signing

src/cryptonote_basic/cryptonote_basic.h

@@ -450,6 +450,7 @@ namespace cryptonote
     uint64_t timestamp;
     crypto::hash  prev_id;
     uint32_t nonce;
+    crypto::signature signature;
 
     BEGIN_SERIALIZE()
       VARINT_FIELD(major_version)
@@ -457,6 +458,8 @@ namespace cryptonote
       VARINT_FIELD(timestamp)
       FIELD(prev_id)
       FIELD(nonce)
+      if (major_version >= BLOCK_HEADER_MINER_SIG)
+          FIELD(signature)
     END_SERIALIZE()
   };
 

src/cryptonote_basic/cryptonote_boost_serialization.h

@@ -185,6 +185,10 @@ namespace boost
     a & b.timestamp;
     a & b.prev_id;
     a & b.nonce;
+    if (b.major_version >= BLOCK_HEADER_MINER_SIG)
+    {
+      a & b.signature;
+    }
     //------------------
     a & b.miner_tx;
     a & b.tx_hashes;

src/cryptonote_basic/cryptonote_format_utils.cpp

@@ -1286,6 +1286,25 @@ namespace cryptonote
     return p;
   }
   //---------------------------------------------------------------
+  crypto::hash get_sig_data(const block& b)
+  {
+    crypto::hash sig_data;
+    blobdata blob = get_block_hashing_blob_sig_data(b);
+    crypto::cn_fast_hash(blob.data(), blob.size(), sig_data);
+    return sig_data;
+  }
+  //---------------------------------------------------------------
+  blobdata get_block_hashing_blob_sig_data(const block& b)
+  {
+    block_header tmp = static_cast<const block_header&>(b);
+    memset(&tmp.signature, 0, sizeof(tmp.signature));
+    blobdata blob = t_serializable_object_to_blob(tmp);
+    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;
+  }
+  //---------------------------------------------------------------
   std::vector<uint64_t> relative_output_offsets_to_absolute(const std::vector<uint64_t>& off)
   {
     std::vector<uint64_t> res = off;

src/cryptonote_basic/cryptonote_format_utils.h

@@ -120,6 +120,8 @@ namespace cryptonote
   bool calculate_block_hash(const block& b, crypto::hash& res, const blobdata_ref *blob = NULL);
   bool get_block_hash(const block& b, crypto::hash& res);
   crypto::hash get_block_hash(const block& b);
+  crypto::hash get_sig_data(const block& b);
+  blobdata get_block_hashing_blob_sig_data(const block& b);
   bool parse_and_validate_block_from_blob(const blobdata_ref& b_blob, block& b, crypto::hash *block_hash);
   bool parse_and_validate_block_from_blob(const blobdata_ref& b_blob, block& b);
   bool parse_and_validate_block_from_blob(const blobdata_ref& b_blob, block& b, crypto::hash &block_hash);

src/cryptonote_basic/miner.cpp

@@ -99,6 +99,7 @@ namespace cryptonote
     const command_line::arg_descriptor<uint64_t>    arg_bg_mining_min_idle_interval_seconds =  {"bg-mining-min-idle-interval", "Specify min lookback interval in seconds for determining idle state", miner::BACKGROUND_MINING_DEFAULT_MIN_IDLE_INTERVAL_IN_SECONDS, true};
     const command_line::arg_descriptor<uint16_t>     arg_bg_mining_idle_threshold_percentage =  {"bg-mining-idle-threshold", "Specify minimum avg idle percentage over lookback interval", miner::BACKGROUND_MINING_DEFAULT_IDLE_THRESHOLD_PERCENTAGE, true};
     const command_line::arg_descriptor<uint16_t>     arg_bg_mining_miner_target_percentage =  {"bg-mining-miner-target", "Specify maximum percentage cpu use by miner(s)", miner::BACKGROUND_MINING_DEFAULT_MINING_TARGET_PERCENTAGE, true};
+    const command_line::arg_descriptor<std::string> arg_spendkey =  {"spendkey", "Specify secret spend key used for mining", "", true};
   }
 
 
@@ -291,10 +292,22 @@ namespace cryptonote
     command_line::add_arg(desc, arg_bg_mining_min_idle_interval_seconds);
     command_line::add_arg(desc, arg_bg_mining_idle_threshold_percentage);
     command_line::add_arg(desc, arg_bg_mining_miner_target_percentage);
+    command_line::add_arg(desc, arg_spendkey);
   }
   //-----------------------------------------------------------------------------------------------------
   bool miner::init(const boost::program_options::variables_map& vm, network_type nettype)
   {
+    if(command_line::has_arg(vm, arg_spendkey))
+    {
+        std::string skey_str = command_line::get_arg(vm, arg_spendkey);
+        crypto::secret_key spendkey;
+        epee::string_tools::hex_to_pod(skey_str, spendkey);
+        crypto::secret_key viewkey;
+        keccak((uint8_t *)&spendkey, 32, (uint8_t *)&viewkey, 32);
+        sc_reduce32((uint8_t *)&viewkey);
+        m_spendkey = spendkey;
+        m_viewkey = viewkey;
+    }
     if(command_line::has_arg(vm, arg_extra_messages))
     {
       std::string buff;
@@ -573,6 +586,27 @@ namespace cryptonote
       }
 
       b.nonce = nonce;
+
+      // Miner Block Header Signing
+      if (b.major_version >= BLOCK_HEADER_MINER_SIG)
+      {
+        // tx key derivation
+        crypto::key_derivation derivation;
+        cryptonote::keypair in_ephemeral;
+        crypto::secret_key eph_secret_key;
+        crypto::public_key tx_pub_key = get_tx_pub_key_from_extra(b.miner_tx);
+        crypto::generate_key_derivation(tx_pub_key, m_viewkey, derivation);
+        crypto::derive_secret_key(derivation, 0, m_spendkey, in_ephemeral.sec);
+        eph_secret_key = in_ephemeral.sec;
+        // keccak hash and sign block header data
+        crypto::signature signature;
+        crypto::hash sig_data = get_sig_data(b);
+        crypto::public_key eph_pub_key = boost::get<txout_to_key>(b.miner_tx.vout[0].target).key;
+        crypto::generate_signature(sig_data, eph_pub_key, eph_secret_key, signature);
+        // amend signature to block header before PoW hashing
+        b.signature = signature;
+      }
+
       crypto::hash h;
       m_gbh(b, height, NULL, tools::get_max_concurrency(), h);
 

src/cryptonote_basic/miner.h

@@ -136,6 +136,8 @@ namespace cryptonote
     i_miner_handler* m_phandler;
     get_block_hash_t m_gbh;
     account_public_address m_mine_address;
+    crypto::secret_key m_spendkey;
+    crypto::secret_key m_viewkey;
     epee::math_helper::once_a_time_seconds<5> m_update_block_template_interval;
     epee::math_helper::once_a_time_seconds<2> m_update_merge_hr_interval;
     epee::math_helper::once_a_time_seconds<1> m_autodetect_interval;

src/cryptonote_config.h

@@ -43,6 +43,7 @@
 #define CURRENT_TRANSACTION_VERSION                     2
 #define CURRENT_BLOCK_MAJOR_VERSION                     7
 #define CURRENT_BLOCK_MINOR_VERSION                     7
+#define BLOCK_HEADER_MINER_SIG                          18
 #define CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V2           300*2
 #define CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT              60*60*2
 #define CRYPTONOTE_DEFAULT_TX_SPENDABLE_AGE             4

src/cryptonote_core/blockchain.cpp

@@ -1377,6 +1377,34 @@ difficulty_type Blockchain::get_next_difficulty_for_alternative_chain(const std:
 //   a non-overflowing tx amount (dubious necessity on this check)
 bool Blockchain::prevalidate_miner_transaction(const block& b, uint64_t height, uint8_t hf_version)
 {
+  // Miner Block Header Signing
+  if (hf_version >= BLOCK_HEADER_MINER_SIG)
+  {
+      // sanity checks
+      if (b.miner_tx.vout.size() != 1)
+      {
+          MWARNING("Only 1 output in miner transaction allowed");
+          return false;
+      }
+      if (b.miner_tx.vout[0].target.type() != typeid(txout_to_key))
+      {
+          MWARNING("Wrong txout type");
+          return false;
+      }
+      // keccak hash block header data and check miner signature
+      // if signature is invalid, reject block
+      crypto::hash sig_data = get_sig_data(b);
+      crypto::signature signature = b.signature;
+      crypto::public_key eph_pub_key = boost::get<txout_to_key>(b.miner_tx.vout[0].target).key;
+      if (!crypto::check_signature(sig_data, eph_pub_key, signature))
+      {
+          MWARNING("Miner signature is invalid");
+          return false;
+      } else {
+          LOG_PRINT_L1("Miner signature is good");
+      }
+  }
+
   LOG_PRINT_L3("Blockchain::" << __func__);
   CHECK_AND_ASSERT_MES(b.miner_tx.vin.size() == 1, false, "coinbase transaction in the block has no inputs");
   CHECK_AND_ASSERT_MES(b.miner_tx.vin[0].type() == typeid(txin_gen), false, "coinbase transaction in the block has the wrong type");

src/rpc/core_rpc_server.cpp

@@ -1934,6 +1934,10 @@ namespace cryptonote
         return false;
       }
       b.nonce = req.starting_nonce;
+      if (b.major_version >= BLOCK_HEADER_MINER_SIG)
+      {
+          b.signature = {};
+      }
       crypto::hash seed_hash = crypto::null_hash;
       if (b.major_version >= RX_BLOCK_VERSION && !epee::string_tools::hex_to_pod(template_res.seed_hash, seed_hash))
       {

src/rpc/daemon_handler.cpp

@@ -895,6 +895,10 @@ namespace rpc
     header.minor_version = b.minor_version;
     header.timestamp = b.timestamp;
     header.nonce = b.nonce;
+    if (b.major_version >= BLOCK_HEADER_MINER_SIG)
+    {
+      header.signature = b.signature;
+    }
     header.prev_id = b.prev_id;
 
     header.depth = m_core.get_current_blockchain_height() - header.height - 1;

src/rpc/message_data_structs.h

@@ -164,6 +164,7 @@ namespace rpc
     uint64_t timestamp;
     crypto::hash  prev_id;
     uint32_t nonce;
+    crypto::signature signature;
     uint64_t height;
     uint64_t depth;
     crypto::hash hash;

src/serialization/json_object.cpp

@@ -312,6 +312,7 @@ void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const cryptonote::b
   INSERT_INTO_JSON_OBJECT(dest, timestamp, b.timestamp);
   INSERT_INTO_JSON_OBJECT(dest, prev_id, b.prev_id);
   INSERT_INTO_JSON_OBJECT(dest, nonce, b.nonce);
+  INSERT_INTO_JSON_OBJECT(dest, signature, b.signature);
   INSERT_INTO_JSON_OBJECT(dest, miner_tx, b.miner_tx);
   INSERT_INTO_JSON_OBJECT(dest, tx_hashes, b.tx_hashes);
 
@@ -331,6 +332,7 @@ void fromJsonValue(const rapidjson::Value& val, cryptonote::block& b)
   GET_FROM_JSON_OBJECT(val, b.timestamp, timestamp);
   GET_FROM_JSON_OBJECT(val, b.prev_id, prev_id);
   GET_FROM_JSON_OBJECT(val, b.nonce, nonce);
+  GET_FROM_JSON_OBJECT(val, b.signature, signature);
   GET_FROM_JSON_OBJECT(val, b.miner_tx, miner_tx);
   GET_FROM_JSON_OBJECT(val, b.tx_hashes, tx_hashes);
 }