Added assignment3 Main.java

assignment3/Main.java

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+/*
+ * Main test code for Cousera cryptocurrency assignment3
+ * Based on code by Sven Mentl and Pietro Brunetti
+ * 
+ * Copyright:
+ * - Sven Mentl
+ * - Pietro Brunetti
+ * - Bruce Arden
+ * - Tero Keski-Valkama
+ */
+
+import java.math.BigInteger;
+import java.security.*;
+
+public class Main {
+
+   public static void main(String[] args) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidKeyException, SignatureException {
+
+        /*
+         * Generate key pairs, for Scrooge, Alice & Bob
+         */
+        KeyPair pk_scrooge = KeyPairGenerator.getInstance("RSA").generateKeyPair();
+        KeyPair pk_alice   = KeyPairGenerator.getInstance("RSA").generateKeyPair();
+        KeyPair pk_bob     = KeyPairGenerator.getInstance("RSA").generateKeyPair();
+
+	/*
+         * Create Genesis block: No TXs, but 1 Coinbase
+         */
+	Block genesis = new Block(null, pk_scrooge.getPublic());
+	genesis.finalize();
+	BlockChain bc = new BlockChain(genesis);
+	BlockHandler bh = new BlockHandler(bc);
+
+	/*
+	 * Create block1 from alice with tx scrooge -> alice
+         */
+	Block block1 = new Block(genesis.getHash(), pk_alice.getPublic());
+        // new TX: scrooge pays 25 coins to alice
+        Tx tx1 = new Tx();
+
+        // the genesis block has a value of 25
+        tx1.addInput(genesis.getCoinbase().getHash(), 0);
+
+        tx1.addOutput(5, pk_alice.getPublic());
+        tx1.addOutput(10, pk_alice.getPublic());
+        tx1.addOutput(10, pk_alice.getPublic());
+
+        // There is only one (at position 0) Transaction.Input in tx2
+        // and it contains the coin from Scrooge, therefore I have to sign with the private key from Scrooge
+        tx1.signTx(pk_scrooge.getPrivate(), 0);
+
+	block1.addTransaction(tx1);
+	block1.finalize();
+
+	System.out.println("Block1 Added ok: " + bh.processBlock(block1));
+
+	/*
+	 * Create alternative block, block2 from scrooge with tx scrooge -> scrooge
+         */
+	Block block2 = new Block(genesis.getHash(), pk_scrooge.getPublic());
+
+        // new TX: scrooge pays 25 coins to scrooge
+        Tx tx2 = new Tx();
+        tx2.addInput(genesis.getCoinbase().getHash(), 0);  //25
+        tx2.addOutput(5, pk_scrooge.getPublic());
+        tx2.addOutput(10, pk_scrooge.getPublic());
+        tx2.addOutput(10, pk_scrooge.getPublic());
+        tx2.signTx(pk_scrooge.getPrivate(), 0);
+
+	block2.addTransaction(tx2);
+	block2.finalize();
+
+	System.out.println("Block2 Added ok: " + bh.processBlock(block2));
+
+	/*
+	 * Create new block3 chained to block1 with tx alice -> bob
+         */
+	Block block3 = new Block(block1.getHash(), pk_scrooge.getPublic());
+
+        // new TX: alice pays 15 coins to bob
+        Tx tx3 = new Tx();
+        tx3.addOutput(20, pk_bob.getPublic());
+        tx3.addInput(tx1.getHash(), 1);	// 10 coins
+        tx3.signTx(pk_alice.getPrivate(), 0);
+        tx3.addInput(tx1.getHash(), 2);	// 10 coins
+        tx3.signTx(pk_alice.getPrivate(), 1);
+
+	block3.addTransaction(tx3);
+	block3.finalize();
+
+	System.out.println("Block3 Added ok: " + bh.processBlock(block3));
+
+	/*
+	 * Create new block4 chained to block3 with tx bob -> bob
+         */
+	Block block4 = new Block(block3.getHash(), pk_scrooge.getPublic());
+
+        // new TX: bob splits 15 coins to bob
+        Tx tx4 = new Tx();
+        tx4.addOutput(10, pk_bob.getPublic());
+        tx4.addOutput(5, pk_bob.getPublic());
+        tx4.addInput(tx3.getHash(), 0);	// 15 coins
+        tx4.signTx(pk_bob.getPrivate(), 0);
+
+	block4.addTransaction(tx4);
+	block4.finalize();
+
+	System.out.println("Block4 Added ok: " + bh.processBlock(block4));
+
+	/*
+	 * Create new block5 chained to block4 with tx alice -> bob
+	 */
+	Block block5 = new Block(block4.getHash(), pk_alice.getPublic());
+
+	// new TX: alice pays 5+25 coins to bob
+        Tx tx5 = new Tx();
+        tx5.addOutput(25, pk_bob.getPublic());
+        tx5.addInput(tx1.getHash(), 0);	// 5 coins
+        tx5.signTx(pk_alice.getPrivate(), 0);
+        tx5.addInput(block1.getCoinbase().getHash(), 0); // 25 coins
+        tx5.signTx(pk_alice.getPrivate(), 1);
+
+	block5.addTransaction(tx5);
+	block5.finalize();
+	System.out.println("Block5 Added ok: " + bh.processBlock(block5));
+
+    }
+
+
+    public static class Tx extends Transaction { 
+        public void signTx(PrivateKey sk, int input) throws SignatureException {
+            Signature sig = null;
+            try {
+                sig = Signature.getInstance("SHA256withRSA");
+                sig.initSign(sk);
+                sig.update(this.getRawDataToSign(input));
+            } catch (NoSuchAlgorithmException | InvalidKeyException e) {
+                throw new RuntimeException(e);
+            }
+            this.addSignature(sig.sign(),input);
+            // Note that this method is incorrectly named, and should not in fact override the Java
+            // object finalize garbage collection related method.
+            this.finalize();
+        }
+    }
+}