Java reviewideas addblockchain

.classpath

@@ -29,5 +29,6 @@
 		</attributes>
 	</classpathentry>
 	<classpathentry kind="lib" path="src/main/resources/tools.jar"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/5"/>
 	<classpathentry kind="output" path="target/classes"/>
 </classpath>

README.md

@@ -1,8 +1,11 @@
 # DiversTestsJava
 Quelques tests de programmation en Java, des notes diverses, 
 
-    * JDBC local (avec un peu de MySQL)
-    * OAuth
-    * Challenge CybserSec
-    * Java Swing : Full Screen, SpalshScreen (à revoir / préciser)
-    * Java reflect / réflexivité / introspection
+  * JDBC local (avec un peu de MySQL)
+  * OAuth
+  * Socket implementation
+  * HTTP use
+  * Challenge CybserSec (quelques notes)
+  * Java Swing : Full Screen, SpalshScreen (à revoir / préciser)
+  * Java reflect / réflexivité / introspection
+  * "blockchain"

pom.xml

@@ -48,5 +48,21 @@
 			<artifactId>utilities</artifactId>
 			<version>0.0.2-SNAPSHOT</version>
 		</dependency>
+
+		<!-- For cryptocurrencies tests and tutorials -->
+		<!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
+		<dependency>
+			<groupId>com.google.code.gson</groupId>
+			<artifactId>gson</artifactId>
+			<version>2.8.8</version>
+		</dependency>
+		<!-- https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk15to18 -->
+		<dependency>
+			<groupId>org.bouncycastle</groupId>
+			<artifactId>bcprov-jdk15to18</artifactId>
+			<version>1.69</version>
+		</dependency>
+
+
 	</dependencies>
 </project>

src/main/java/NoobChainTests.java

@@ -0,0 +1,127 @@
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.security.Security;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import com.google.gson.GsonBuilder;
+
+import gabywald.crypto.blockchain.Block;
+import gabywald.crypto.blockchain.BlockChain;
+import gabywald.crypto.blockchain.StringUtils;
+import gabywald.crypto.blockchain.Transaction;
+import gabywald.crypto.blockchain.Wallet;
+
+/**
+ * Tests about BlockChain / NoobChain. 
+ * @author Gabriel Chandesris (2021)
+ */
+class NoobChainTests {
+
+	/**
+	 * Test : block. 
+	 */
+	@Test
+	void testPart01() {
+		Block genesisBlock = new Block("Hi im the first block", "0");
+		Assertions.assertNotNull( genesisBlock );
+		System.out.println("Hash for block 1 : " + genesisBlock.getHash() );
+		Assertions.assertNotNull( genesisBlock.getHash() );
+
+		Block secondBlock = new Block("Yo im the second block", genesisBlock.getHash() );
+		Assertions.assertNotNull( secondBlock );
+		System.out.println("Hash for block 2 : " + secondBlock.getHash() );
+		Assertions.assertNotNull( secondBlock.getHash() );
+
+		Block thirdBlock = new Block("Hey im the third block", secondBlock.getHash() );
+		Assertions.assertNotNull( thirdBlock );
+		System.out.println("Hash for block 3 : " + thirdBlock.getHash() );
+		Assertions.assertNotNull( thirdBlock.getHash() );
+	}
+
+	/**
+	 * Test : blockchain
+	 */
+	@Test
+	void testPart02() {
+		List<Block> blockchain = new ArrayList<Block>(); 
+		// Add our blocks to the blockchain List:
+		blockchain.add(new Block("Hi im the first block", "0"));		
+		blockchain.add(new Block("Yo im the second block", blockchain.get(blockchain.size()-1).getHash() )); 
+		blockchain.add(new Block("Hey im the third block",  blockchain.get(blockchain.size()-1).getHash() ));
+		Assertions.assertEquals(3,  blockchain.size());
+		String blockchainJson = new GsonBuilder().setPrettyPrinting().create().toJson(blockchain);
+		Assertions.assertNotNull( blockchainJson );
+		System.out.println(blockchainJson);
+	}
+
+	@Test
+	void testPart03() {
+		List<Block> blockchain = new ArrayList<Block>();
+		int difficulty = 3;
+		// Add our blocks to the blockchain List:
+		blockchain.add(new Block("Hi im the first block", "0"));
+		System.out.println("Trying to Mine block 1... ");
+		blockchain.get(0).mineBlock(difficulty);
+
+		blockchain.add(new Block("Yo im the second block", blockchain.get(blockchain.size()-1).getHash() ));
+		System.out.println("Trying to Mine block 2... ");
+		blockchain.get(1).mineBlock(difficulty);
+
+		blockchain.add(new Block("Hey im the third block", blockchain.get(blockchain.size()-1).getHash() ));
+		System.out.println("Trying to Mine block 3... ");
+		blockchain.get(2).mineBlock(difficulty);
+
+		Assertions.assertEquals(3,  blockchain.size());
+
+		System.out.println("\nBlockchain is Valid: " + BlockChain.isChainValidV1( blockchain ));
+
+		Assertions.assertTrue( BlockChain.isChainValidV1( blockchain ) );
+
+		String blockchainJson = new GsonBuilder().setPrettyPrinting().create().toJson(blockchain);
+
+		Assertions.assertNotNull( blockchainJson );
+
+		System.out.println("\nThe block chain: ");
+		System.out.println(blockchainJson);
+	}
+
+	@Test
+	void testPart04() {
+		// Setup Bouncey castle as a Security Provider
+		Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); 
+		// Security.addProvider(new sun.security.provider.Sun());
+		// XXX NOTE see https://docs.oracle.com/javase/8/docs/technotes/guides/security/SunProviders.html
+		// Create the new wallets
+		Wallet walletA = new Wallet();
+		Wallet walletB = new Wallet();
+		Assertions.assertNotNull( walletA );
+		Assertions.assertNotNull( walletB );
+		// Test public and private keys
+		System.out.println("Private and public keys:");
+		System.out.println(StringUtils.getStringFromKey(walletA.privateKey));
+		System.out.println(StringUtils.getStringFromKey(walletA.publicKey));
+		Assertions.assertNotNull( walletA.privateKey );
+		Assertions.assertNotNull( walletA.publicKey );
+		Assertions.assertNotNull( walletB.privateKey );
+		Assertions.assertNotNull( walletB.publicKey );
+		//Create a test transaction from WalletA to walletB 
+		Transaction transaction = new Transaction(walletA.publicKey, walletB.publicKey, 5, null);
+		Assertions.assertNotNull( transaction );
+		transaction.generateSignature(walletA.privateKey);
+		Assertions.assertNotNull( walletA.privateKey );
+		//Verify the signature works and verify it from the public key
+		System.out.println("Is signature verified");
+		System.out.println(transaction.verifySignature());
+		Assertions.assertTrue( transaction.verifySignature() );
+	}
+
+	@Test
+	void testPart05() {
+		fail("Not yet implemented");
+	}
+
+}

src/main/java/gabywald/crypto/blockchain/Block.java

@@ -0,0 +1,123 @@
+package gabywald.crypto.blockchain;
+
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Block of BlockChain. 
+ * <br/><a href="https://medium.com/programmers-blockchain/create-simple-blockchain-java-tutorial-from-scratch-6eeed3cb03fa">https://medium.com/programmers-blockchain/create-simple-blockchain-java-tutorial-from-scratch-6eeed3cb03fa</a>
+ * <br/><a href="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/CryptoKass/NoobChain-Tutorial-Part-1">https://github.com/CryptoKass/NoobChain-Tutorial-Part-1</a>
+ * @author Gabriel Chandesris (2021)
+ */
+public class Block {
+
+	private String hash;
+	private String previousHash; 
+	/** Our data will be a simple message. */
+	// private String data;
+	/** As number of milliseconds since 1/1/1970. */
+	private long timeStamp;
+	private int nonce;
+
+	private String merkleRoot;
+
+	private List<Transaction> transactions = new ArrayList<Transaction>(); 
+
+	/**
+	 * Block Constructor. 
+	 * @param data
+	 * @param previousHash
+	 */
+	public Block(String data, String previousHash ) {
+		// this.data = data;
+		this.previousHash = previousHash;
+		this.timeStamp = new Date().getTime();
+		// Making sure we do this after we set the other values.
+		this.hash = this.calculateHash();
+	}
+
+	/**
+	 * Block Constructor. 
+	 * @param previousHash
+	 */
+	public Block(String previousHash ) {
+		this(null, previousHash);
+	}
+
+	/**
+	 * Calculate new hash based on blocks contents
+	 * @return (null if exception apply internally). 
+	 * @see StringUtils#applySha256(String)
+	 */
+	public String calculateHash() {
+		String calculatedhash = null;
+		try {
+			calculatedhash = StringUtils.applySha256( 
+					previousHash +
+					Long.toString(timeStamp) +
+					Integer.toString(nonce) + 
+					merkleRoot
+					);
+		} catch (BlockchainException e) {
+			// e.printStackTrace();
+			System.out.println( e.getMessage() );
+			calculatedhash = null;
+		}
+		return calculatedhash;
+	}
+
+	/**
+	 * Mining block
+	 * @param difficulty
+	 */
+	public void mineBlock(int difficulty) {
+		this.merkleRoot = StringUtils.getMerkleRoot(this.transactions);
+		// Create a string with difficulty * "0"
+		String target = StringUtils.getDifficultyString(difficulty);
+		while ( (this.hash == null) || ( ! this.hash.substring( 0, difficulty ).equals(target)) ) {
+			this.nonce++;
+			this.hash = this.calculateHash();
+			// XXX NOTE if exception inside calculateHash : hash will be null !
+		}
+		System.out.println("Block Mined!!! : " + this.hash);
+	}
+
+	/**
+	 * Add transactions to this block. 
+	 * @param transaction
+	 * @param UTXOs
+	 * @param minimumTransaction
+	 * @return (boolean)
+	 */
+	public boolean addTransaction(	final Transaction transaction, 
+									final Map<String, TransactionOutput> UTXOs, 
+									final float minimumTransaction) {
+		// Process transaction and check if valid, unless block is genesis block then ignore.
+		if (transaction == null) { return false; }		
+		if (this.previousHash != "0") {
+			if (transaction.processTransaction(UTXOs, minimumTransaction) != true) {
+				System.out.println("Transaction failed to process. Discarded.");
+				return false;
+			}
+		}
+		this.transactions.add(transaction);
+		System.out.println("Transaction Successfully added to Block");
+		return true;
+	}
+
+	public String getHash() 
+		{ return this.hash; }
+
+	public String getPreviousHash() 
+		{ return this.previousHash; }
+
+	public String getMerkleRoot() 
+		{ return this.merkleRoot; }
+
+	public List<Transaction> getTransactions() 
+		{ return this.transactions; }
+
+
+}