Day 3: 区块的构造

qikh · qikh · commit 08cbfc755701 · 2017-02-07T17:38:25.000+08:00
diff --git a/src/main/kotlin/mbc/core/Block.kt b/src/main/kotlin/mbc/core/Block.kt
@@ -0,0 +1,18 @@
+package mbc.core
+
+import mbc.util.CryptoUtil
+import org.joda.time.DateTime
+
+/**
+ * 区块(Block)类，包含了区块高度(height)，上一个区块哈希值(parentHash)，旷工账户地址(minerAddress)，交易列表(transactions)和时间戳(time)。
+ */
+class Block(val height: Long, val parentHash: ByteArray, val minerAddress: String, val transactions: List<Transaction>,
+            val time: DateTime) {
+
+  /**
+   * 区块(Block)的哈希值(KECCAK-256)
+   */
+  val hash: ByteArray
+    get() = CryptoUtil.hashBlock(this)
+
+}
diff --git a/src/main/kotlin/mbc/core/BlockChain.kt b/src/main/kotlin/mbc/core/BlockChain.kt
@@ -0,0 +1,23 @@
+package mbc.core
+
+import mbc.core.TransactionExecutor.applyTrx
+import org.joda.time.DateTime
+
+/**
+ * 区块链(BlockChain)管理类，负责区块的生成、发布、计算等功能。
+ */
+class BlockChain(val minerAddress: String) {
+
+  /**
+   * 构造新的区块，要素信息为：区块高度(height)，父区块的哈希值(parentHash), 交易记录(transactions)，时间戳(time)
+   */
+  fun createNewBlock(parent: Block, transactions: List<Transaction>): Block {
+    val block = Block(parent.height + 1, parent.hash, minerAddress, transactions, DateTime())
+
+    for (trx in transactions) {
+      applyTrx(trx)
+    }
+
+    return block
+  }
+}
diff --git a/src/main/kotlin/mbc/util/CryptoUtil.kt b/src/main/kotlin/mbc/util/CryptoUtil.kt
@@ -1,8 +1,10 @@
 package mbc.util
 
+import mbc.core.Block
 import mbc.core.Transaction
 import org.spongycastle.jce.provider.BouncyCastleProvider
 import org.spongycastle.util.encoders.Hex
+import java.nio.ByteBuffer
 import java.security.*
 import java.security.Security.insertProviderAt
 import java.security.spec.ECGenParameterSpec
@@ -46,7 +48,7 @@ class CryptoUtil {
     fun signTransaction(trx: Transaction, privateKey: PrivateKey): ByteArray {
       val signer = Signature.getInstance("SHA256withECDSA")
       signer.initSign(privateKey)
-      val msgToSign = getTransactionContentToSign(trx)
+      val msgToSign = encodeTransaction(trx)
       signer.update(msgToSign)
       return signer.sign()
     }
@@ -58,13 +60,38 @@ class CryptoUtil {
       val signer = Signature.getInstance("SHA256withECDSA")
       signer.initVerify(trx.publicKey)
 
-      signer.update(getTransactionContentToSign(trx))
+      signer.update(encodeTransaction(trx))
       return signer.verify(signature)
     }
 
-    private fun getTransactionContentToSign(
+    /**
+     * 运算区块的哈希值。
+     */
+    fun hashBlock(block: Block): ByteArray {
+      val digest = MessageDigest.getInstance("KECCAK-256", "SC")
+      digest.update(encodeBlock(block))
+      return digest.digest()
+    }
+
+    /**
+     * 序列化交易(Transaction)。当前实现非常简单，后期会改成以太坊的RLP协议。
+     */
+    private fun encodeTransaction(
         trx: Transaction) = (trx.senderAddress + trx.receiverAddress + trx.amount.toString() + trx.time.millis.toString()).toByteArray()
 
+    /**
+     * 序列化区块(Block)。当前实现非常简单，后期会改成以太坊的RLP协议。
+     */
+    private fun encodeBlock(block: Block): ByteArray {
+      val byteBuffer = ByteBuffer.allocate(1024)
+      byteBuffer.put(block.minerAddress.toByteArray())
+      byteBuffer.put(block.time.millis.toString().toByteArray())
+      block.transactions.map { byteBuffer.put(encodeTransaction(it)) }
+
+      byteBuffer.flip()
+      return byteBuffer.array()
+    }
+
   }
 
 }
diff --git a/src/test/kotlin/mbc/core/BlockChainTest.kt b/src/test/kotlin/mbc/core/BlockChainTest.kt
@@ -115,4 +115,41 @@ class BlockChainTest {
     assert(trx.isValid)
   }
 
+  /**
+   * 构造新的区块
+   */
+  @Test fun createBlockTest() {
+    // 初始化Alice账户
+    val kp1 = generateKeyPair() ?: return
+    val alice = Account(kp1.public)
+
+    // 初始化Bob账户
+    val kp2 = generateKeyPair() ?: return
+    val bob = Account(kp2.public)
+
+    // 初始金额为200
+    addAmount(alice.address, 200)
+    addAmount(bob.address, 200)
+
+    // Alice向Bob转账100
+    val trx = Transaction(alice.address, bob.address, 100, DateTime(), kp1.public)
+    // Alice用私钥签名
+    trx.sign(kp1.private)
+
+    // 初始化矿工Charlie账户
+    val kp3 = generateKeyPair() ?: return
+    val charlie = Account(kp3.public)
+
+    // 构造原始区块(高度为0)
+    val genesisBlock = Block(0, ByteArray(0), "1234567890123456789012345678901234567890", emptyList(), DateTime(2017,2,1,0,0))
+
+    // 构造新的区块
+    val blockChain = BlockChain(charlie.address)
+    blockChain.createNewBlock(genesisBlock, listOf(trx))
+
+    // 查询余额是否正确
+    assert(alice.balance == 100L)
+    assert(bob.balance == 300L)
+  }
+
 }
