diff --git a/src/noobchain/Block.java b/src/noobchain/Block.java
index 7986167..122a917 100644
--- a/src/noobchain/Block.java
+++ b/src/noobchain/Block.java
@@ -43,19 +43,19 @@ public void mineBlock(int difficulty) {
 	}
 	
 	//Add transactions to this block
-	public boolean addTransaction(Transaction transaction) {
+	public void addTransaction(Transaction transaction) throws IllegalStateException {
 		//process transaction and check if valid, unless block is genesis block then ignore.
 		if(transaction == null) return false;		
 		if((!"0".equals(previousHash))) {
 			if((transaction.processTransaction() != true)) {
 				System.out.println("Transaction failed to process. Discarded.");
-				return false;
+				throw new IllegalStateException("Transaction failed to process. Discarded.");
 			}
 		}
 
 		transactions.add(transaction);
 		System.out.println("Transaction Successfully added to Block");
-		return true;
+	
 	}
 	
 }
diff --git a/src/noobchain/NoobChain.java b/src/noobchain/NoobChain.java
index 3d306f2..af9c54e 100644
--- a/src/noobchain/NoobChain.java
+++ b/src/noobchain/NoobChain.java
@@ -1,4 +1,5 @@
 package noobchain;
+
 import java.security.Security;
 import java.util.ArrayList;
 //import java.util.Base64;
@@ -7,141 +8,161 @@
 import java.util.Map;
 
 public class NoobChain {
-	
+
 	public static ArrayList<Block> blockchain = new ArrayList<Block>();
-	public static HashMap<String,TransactionOutput> UTXOs = new HashMap<String,TransactionOutput>();
-	
+	public static HashMap<String, TransactionOutput> UTXOs = new HashMap<String, TransactionOutput>();
+
 	public static int difficulty = 3;
 	public static float minimumTransaction = 0.1f;
 	public static Wallet walletA;
 	public static Wallet walletB;
 	public static Transaction genesisTransaction;
 
-	public static void main(String[] args) {	
-		//add our blocks to the blockchain ArrayList:
-		Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); //Setup Bouncey castle as a Security Provider
-		
-		//Create wallets:
+	public static void main(String[] args) {
+		// add our blocks to the blockchain ArrayList:
+		Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); // Setup Bouncey castle as a
+																						// Security Provider
+
+		// Create wallets:
 		walletA = new Wallet();
-		walletB = new Wallet();		
+		walletB = new Wallet();
 		Wallet coinbase = new Wallet();
-		
-		//create genesis transaction, which sends 100 NoobCoin to walletA: 
-		genesisTransaction = new Transaction(coinbase.publicKey, walletA.publicKey, 100f, null);
-		genesisTransaction.generateSignature(coinbase.privateKey);	 //manually sign the genesis transaction	
-		genesisTransaction.transactionId = "0"; //manually set the transaction id
-		genesisTransaction.outputs.add(new TransactionOutput(genesisTransaction.reciepient, genesisTransaction.value, genesisTransaction.transactionId)); //manually add the Transactions Output
-		UTXOs.put(genesisTransaction.outputs.get(0).id, genesisTransaction.outputs.get(0)); //its important to store our first transaction in the UTXOs list.
-		
-		System.out.println("Creating and Mining Genesis block... ");
-		Block genesis = new Block("0");
-		genesis.addTransaction(genesisTransaction);
-		addBlock(genesis);
-		
-		//testing
-		Block block1 = new Block(genesis.hash);
-		System.out.println("\nWalletA's balance is: " + walletA.getBalance());
-		System.out.println("\nWalletA is Attempting to send funds (40) to WalletB...");
-		block1.addTransaction(walletA.sendFunds(walletB.publicKey, 40f));
-		addBlock(block1);
-		System.out.println("\nWalletA's balance is: " + walletA.getBalance());
-		System.out.println("WalletB's balance is: " + walletB.getBalance());
-		
-		Block block2 = new Block(block1.hash);
-		System.out.println("\nWalletA Attempting to send more funds (1000) than it has...");
-		block2.addTransaction(walletA.sendFunds(walletB.publicKey, 1000f));
-		addBlock(block2);
-		System.out.println("\nWalletA's balance is: " + walletA.getBalance());
-		System.out.println("WalletB's balance is: " + walletB.getBalance());
-		
-		Block block3 = new Block(block2.hash);
-		System.out.println("\nWalletB is Attempting to send funds (20) to WalletA...");
-		block3.addTransaction(walletB.sendFunds( walletA.publicKey, 20));
-		System.out.println("\nWalletA's balance is: " + walletA.getBalance());
-		System.out.println("WalletB's balance is: " + walletB.getBalance());
-		
-		isChainValid();
-		
+
+		// create genesis transaction, which sends 100 NoobCoin to walletA:
+		try {
+			genesisTransaction = new Transaction(coinbase.publicKey, walletA.publicKey, 100f, null);
+			genesisTransaction.generateSignature(coinbase.privateKey); // manually sign the genesis transaction
+			genesisTransaction.transactionId = "0"; // manually set the transaction id
+			genesisTransaction.outputs.add(new TransactionOutput(genesisTransaction.reciepient,
+					genesisTransaction.value, genesisTransaction.transactionId)); // manually add the Transactions
+																					// Output
+			UTXOs.put(genesisTransaction.outputs.get(0).id, genesisTransaction.outputs.get(0)); // its important to
+																								// store our first
+																								// transaction in the
+																								// UTXOs list.
+
+			System.out.println("Creating and Mining Genesis block... ");
+			Block genesis = new Block("0");
+			genesis.addTransaction(genesisTransaction);
+			addBlock(genesis);
+
+			// testing
+			Block block1 = new Block(genesis.hash);
+			System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+			System.out.println("\nWalletA is Attempting to send funds (40) to WalletB...");
+			block1.addTransaction(walletA.sendFunds(walletB.publicKey, 40f));
+			addBlock(block1);
+			System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+			System.out.println("WalletB's balance is: " + walletB.getBalance());
+
+			Block block2 = new Block(block1.hash);
+			System.out.println("\nWalletA Attempting to send more funds (1000) than it has...");
+			block2.addTransaction(walletA.sendFunds(walletB.publicKey, 1000f));
+			addBlock(block2);
+			System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+			System.out.println("WalletB's balance is: " + walletB.getBalance());
+
+			Block block3 = new Block(block2.hash);
+			System.out.println("\nWalletB is Attempting to send funds (20) to WalletA...");
+			block3.addTransaction(walletB.sendFunds(walletA.publicKey, 20));
+			System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+			System.out.println("WalletB's balance is: " + walletB.getBalance());
+
+			isChainValid();
+		} catch (Exception e) {
+			// TODO: handle exception
+			System.out.println(e.getMessage());
+		}
+
 	}
-	
+
 	public static Boolean isChainValid() {
-		Block currentBlock; 
+		Block currentBlock;
 		Block previousBlock;
 		String hashTarget = new String(new char[difficulty]).replace('\0', '0');
-		HashMap<String,TransactionOutput> tempUTXOs = new HashMap<String,TransactionOutput>(); //a temporary working list of unspent transactions at a given block state.
+		HashMap<String, TransactionOutput> tempUTXOs = new HashMap<String, TransactionOutput>(); // a temporary working
+																									// list of unspent
+																									// transactions at a
+																									// given block
+																									// state.
 		tempUTXOs.put(genesisTransaction.outputs.get(0).id, genesisTransaction.outputs.get(0));
-		
-		//loop through blockchain to check hashes:
-		for(int i=1; i < blockchain.size(); i++) {
-			
+
+		// loop through blockchain to check hashes:
+		for (int i = 1; i < blockchain.size(); i++) {
+
 			currentBlock = blockchain.get(i);
-			previousBlock = blockchain.get(i-1);
-			//compare registered hash and calculated hash:
-			if(!currentBlock.hash.equals(currentBlock.calculateHash()) ){
+			previousBlock = blockchain.get(i - 1);
+			// compare registered hash and calculated hash:
+			if (!currentBlock.hash.equals(currentBlock.calculateHash())) {
 				System.out.println("#Current Hashes not equal");
 				return false;
 			}
-			//compare previous hash and registered previous hash
-			if(!previousBlock.hash.equals(currentBlock.previousHash) ) {
+			// compare previous hash and registered previous hash
+			if (!previousBlock.hash.equals(currentBlock.previousHash)) {
 				System.out.println("#Previous Hashes not equal");
 				return false;
 			}
-			//check if hash is solved
-			if(!currentBlock.hash.substring( 0, difficulty).equals(hashTarget)) {
+			// check if hash is solved
+			if (!currentBlock.hash.substring(0, difficulty).equals(hashTarget)) {
 				System.out.println("#This block hasn't been mined");
 				return false;
 			}
-			
-			//loop thru blockchains transactions:
+
+			// loop thru blockchains transactions:
 			TransactionOutput tempOutput;
-			for(int t=0; t <currentBlock.transactions.size(); t++) {
+			for (int t = 0; t < currentBlock.transactions.size(); t++) {
 				Transaction currentTransaction = currentBlock.transactions.get(t);
-				
-				if(!currentTransaction.verifySignature()) {
+
+				if (!currentTransaction.verifySignature()) {
 					System.out.println("#Signature on Transaction(" + t + ") is Invalid");
-					return false; 
+					return false;
 				}
-				if(currentTransaction.getInputsValue() != currentTransaction.getOutputsValue()) {
+				if (currentTransaction.getInputsValue() != currentTransaction.getOutputsValue()) {
 					System.out.println("#Inputs are note equal to outputs on Transaction(" + t + ")");
-					return false; 
+					return false;
 				}
-				
-				for(TransactionInput input: currentTransaction.inputs) {	
+
+				for (TransactionInput input : currentTransaction.inputs) {
 					tempOutput = tempUTXOs.get(input.transactionOutputId);
-					
-					if(tempOutput == null) {
+
+					if (tempOutput == null) {
 						System.out.println("#Referenced input on Transaction(" + t + ") is Missing");
 						return false;
 					}
-					
-					if(input.UTXO.value != tempOutput.value) {
+
+					if (input.UTXO.value != tempOutput.value) {
 						System.out.println("#Referenced input Transaction(" + t + ") value is Invalid");
 						return false;
 					}
-					
+
 					tempUTXOs.remove(input.transactionOutputId);
 				}
-				
-				for(TransactionOutput output: currentTransaction.outputs) {
+
+				for (TransactionOutput output : currentTransaction.outputs) {
 					tempUTXOs.put(output.id, output);
 				}
-				
-				if( currentTransaction.outputs.get(0).reciepient != currentTransaction.reciepient) {
-					System.out.println("#Transaction(" + t + ") output reciepient is not who it should be");
-					return false;
-				}
-				if( currentTransaction.outputs.get(1).reciepient != currentTransaction.sender) {
-					System.out.println("#Transaction(" + t + ") output 'change' is not sender.");
-					return false;
-				}
-				
+
+				// we dont need this since we verifySignature() already, the msg we signed has
+				// contains information like reciepient .
+				// if( currentTransaction.outputs.get(0).reciepient !=
+				// currentTransaction.reciepient) {
+				// System.out.println("#Transaction(" + t + ") output reciepient is not who it
+				// should be");
+				// return false;
+				// }
+				// if( currentTransaction.outputs.get(1).reciepient !=
+				// currentTransaction.sender) {
+				// System.out.println("#Transaction(" + t + ") output 'change' is not sender.");
+				// return false;
+				// }
+
 			}
-			
+
 		}
 		System.out.println("Blockchain is valid");
 		return true;
 	}
-	
+
 	public static void addBlock(Block newBlock) {
 		newBlock.mineBlock(difficulty);
 		blockchain.add(newBlock);
@@ -149,27 +170,28 @@ public static void addBlock(Block newBlock) {
 }
 
 /*
- * public static void main(String[] args) {	
-		//add our blocks to the blockchain ArrayList:
-		Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); //Setup Bouncey castle as a Security Provider
-		
-		//walletA = new Wallet();
-		//walletB = new Wallet();
-		
-		//System.out.println("Private and public keys:");
-		//System.out.println(StringUtil.getStringFromKey(walletA.privateKey));
-		//System.out.println(StringUtil.getStringFromKey(walletA.publicKey));
-		
-		createGenesis();
-		
-		//Transaction transaction = new Transaction(walletA.publicKey, walletB.publicKey, 5);
-		//transaction.signature = transaction.generateSignature(walletA.privateKey);
-		
-		//System.out.println("Is signature verified:");
-		//System.out.println(transaction.verifiySignature());
-		
-	}
+ * public static void main(String[] args) { //add our blocks to the blockchain
+ * ArrayList: Security.addProvider(new
+ * org.bouncycastle.jce.provider.BouncyCastleProvider()); //Setup Bouncey castle
+ * as a Security Provider
+ * 
+ * //walletA = new Wallet(); //walletB = new Wallet();
+ * 
+ * //System.out.println("Private and public keys:");
+ * //System.out.println(StringUtil.getStringFromKey(walletA.privateKey));
+ * //System.out.println(StringUtil.getStringFromKey(walletA.publicKey));
+ * 
+ * createGenesis();
+ * 
+ * //Transaction transaction = new Transaction(walletA.publicKey,
+ * walletB.publicKey, 5); //transaction.signature =
+ * transaction.generateSignature(walletA.privateKey);
+ * 
+ * //System.out.println("Is signature verified:");
+ * //System.out.println(transaction.verifiySignature());
+ * 
+ * }
  */
 
-//System.out.println("Trying to Mine block 1... ");
-//addBlock(new Block("Hi im the first block", "0"));
+// System.out.println("Trying to Mine block 1... ");
+// addBlock(new Block("Hi im the first block", "0"));