Merge pull request #38 from nguyenphuminh/patch-and-rewrite

Patch and rewrite

config.json

@@ -6,7 +6,6 @@
     "PRIVATE_KEY": "",
     "ENABLE_MINING": false,
     "ENABLE_LOGGING": false,
-    "ENABLE_RPC": false,
-    "SYNC_FROM": "",
+    "ENABLE_RPC": true,
     "ENABLE_CHAIN_REQUEST": false
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "jechain",
-  "version": "0.15.0",
+  "version": "0.16.0",
   "description": "Node for JeChain - an experimental smart contract blockchain network",
   "main": "./index.js",
   "scripts": {

src/consensus/consensus.js

@@ -0,0 +1,46 @@
+const crypto = require("crypto"), SHA256 = message => crypto.createHash("sha256").update(message).digest("hex");
+const Block = require("../core/block");
+const { log16 } = require("../utils/utils");
+const generateMerkleRoot = require("../core/merkle");
+const { BLOCK_REWARD, BLOCK_TIME } = require("../config.json");
+
+async function verifyBlock(newBlock, chainInfo, stateDB) {
+    // Check if the block is valid or not, if yes, we will push it to the chain, update the difficulty, chain state and the transaction pool.
+
+    // A block is valid under these factors:
+    // - The hash of this block is equal to the hash re-generated according to the block's info.
+    // - The block is mined (the hash starts with (4+difficulty) amount of zeros).
+    // - Transactions in the block are valid.
+    // - Block's timestamp is not greater than the current timestamp and is not lower than the previous block's timestamp.
+    // - Block's parentHash is equal to latest block's hash
+    // - The new difficulty can only be greater than 1 or lower than 1 compared to the old difficulty.
+
+    return (
+        SHA256(
+            newBlock.blockNumber.toString()       + 
+            newBlock.timestamp.toString()         + 
+            newBlock.txRoot                       + 
+            newBlock.difficulty.toString()        +
+            chainInfo.latestBlock.hash            +
+            newBlock.nonce.toString()
+        ) === newBlock.hash &&
+        newBlock.hash.startsWith("00000" + Array(Math.floor(log16(chainInfo.difficulty)) + 1).join("0")) &&
+        await Block.hasValidTransactions(newBlock, stateDB) &&
+        newBlock.timestamp > chainInfo.latestBlock.timestamp &&
+        newBlock.timestamp < Date.now() &&
+        chainInfo.latestBlock.hash === newBlock.parentHash &&
+        newBlock.blockNumber - 1 === chainInfo.latestBlock.blockNumber &&
+        newBlock.difficulty === chainInfo.difficulty &&
+        generateMerkleRoot(newBlock.transactions) === newBlock.txRoot
+    )
+}
+
+async function updateDifficulty(newBlock, chainInfo, blockDB) {
+    if (newBlock.blockNumber % 100 === 0) {
+        const oldBlock = await blockDB.get((newBlock.blockNumber - 99).toString());
+
+        chainInfo.difficulty = Math.ceil(chainInfo.difficulty * 100 * BLOCK_TIME / (newBlock.timestamp - oldBlock.timestamp));
+    }
+}
+
+module.exports = { verifyBlock, updateDifficulty };

src/node/message-types.js

@@ -0,0 +1,9 @@
+const TYPE = {
+    NEW_BLOCK: 0,
+    CREATE_TRANSACTION: 1,
+    REQUEST_BLOCK: 2,
+    SEND_BLOCK: 3,
+    HANDSHAKE: 4
+}
+
+module.exports = TYPE;