I09b Der JavaCryptoCoin komplett

Auf dieser Seite sind nur die Klassen-Quellcodes zu finden, die Hauptklasse ist im Artikel I09 Der JavaCryptoCoin komplett zu sehen.

Die Block-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;

public class Block implements Serializable {

	private static final long serialVersionUID = 1984888774694344646L;
	public String hash;
    public String previousHash;
    public String merkleRoot;
    public ArrayList<Transaction> transactions = new ArrayList<>();
    public long timeStamp;
    public int nonce;
    public long mineStartTimeStamp;
    public long mineEndTimeStamp;
    public String difficultyString = "";
    public boolean mined = false;

    public Block(String previousHash) {
        this.previousHash = previousHash;
        this.timeStamp = new Date().getTime();
        this.hash = calculateHash();
    }

    public String calculateHash() {
        String calculatedhash = StringUtil.generateSha256(
                previousHash + 
                Long.toString(timeStamp) + 
                Integer.toString(nonce) + 
                merkleRoot + 
                Long.toString(mineStartTimeStamp)
        );
        return calculatedhash;
    }

    public void mineBlock(int difficulty) {
        mineStartTimeStamp = new Date().getTime();
        merkleRoot = StringUtil.getMerkleRoot(transactions);
        String target = StringUtil.getDifficultyString(difficulty, merkleRoot); 
        while (!hash.substring(0, difficulty).equals(target)) {
            nonce++;
            hash = calculateHash();
        }
        mineEndTimeStamp = new Date().getTime();
        difficultyString = target;
        mined = true;
        System.out.println("Block Mined!!! " + (mineEndTimeStamp - mineStartTimeStamp) + " ms: " + hash);
    }

    public boolean addTransaction(Transaction transaction) {
        if (transaction == null) {
            return false;
        }
        if ((!"0".equals(previousHash)) && !transaction.asReward) {
            if ((transaction.processTransaction() != true)) {
                System.out.println("Die Transaktion konnte nicht bearbeitet werden, der Vorgang wurde abgebrochen.");
                return false;
            }
        }
        transactions.add(transaction);
        System.out.println("Die Transaktion wurde dem Block erfolgreich hinzugefügt");
        return true;
    }
}

package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.io.Serializable;

import java.util.ArrayList;

import java.util.Date;

public class Block implements Serializable {

private static final long serialVersionUID = 1984888774694344646L;

public String hash;

public String previousHash;

public String merkleRoot;

public ArrayList<Transaction> transactions = new ArrayList<>();

public long timeStamp;

public int nonce;

public long mineStartTimeStamp;

public long mineEndTimeStamp;

public String difficultyString = "";

public boolean mined = false;

public Block(String previousHash) {

this.previousHash = previousHash;

this.timeStamp = new Date().getTime();

this.hash = calculateHash();

}

public String calculateHash() {

String calculatedhash = StringUtil.generateSha256(

previousHash +

Long.toString(timeStamp) +

Integer.toString(nonce) +

merkleRoot +

Long.toString(mineStartTimeStamp)

);

return calculatedhash;

}

public void mineBlock(int difficulty) {

mineStartTimeStamp = new Date().getTime();

merkleRoot = StringUtil.getMerkleRoot(transactions);

String target = StringUtil.getDifficultyString(difficulty, merkleRoot);

while (!hash.substring(0, difficulty).equals(target)) {

nonce++;

hash = calculateHash();

}

mineEndTimeStamp = new Date().getTime();

difficultyString = target;

mined = true;

System.out.println("Block Mined!!! " + (mineEndTimeStamp - mineStartTimeStamp) + " ms: " + hash);

}

public boolean addTransaction(Transaction transaction) {

if (transaction == null) {

return false;

}

if ((!"0".equals(previousHash)) && !transaction.asReward) {

if ((transaction.processTransaction() != true)) {

System.out.println("Die Transaktion konnte nicht bearbeitet werden, der Vorgang wurde abgebrochen.");

return false;

}

transactions.add(transaction);

System.out.println("Die Transaktion wurde dem Block erfolgreich hinzugefügt");

return true;

}

Die FileUtil-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class FileUtil {

	public static void saveObject(String filenameString, Object object) {
		try {
			FileOutputStream fo = new FileOutputStream(new File(filenameString));
			ObjectOutputStream oo = new ObjectOutputStream(fo);
			oo.writeObject(object);
			oo.close();
			fo.close();
		} catch (FileNotFoundException e) {
			System.out.println("Datei nicht gefunden");
		} catch (IOException e) {
			System.out.println("Fehler bei der Initialisierung des Streams");
		}
	}

	public static Object loadObject(String filenameString) {
		Object object = null;
		try {
			FileInputStream fi = new FileInputStream(new File(filenameString));
			ObjectInputStream oi = new ObjectInputStream(fi);
			object = (Object) oi.readObject();
			oi.close();
			fi.close();
		} catch (FileNotFoundException e) {
			System.out.println("Datei nicht gefunden");
		} catch (IOException e) {
			System.out.println("Fehler bei der Initialisierung des Streams");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		return object;
	}

	public static void saveJsonFile(String filenameString, String jsonString) throws IOException {
		BufferedWriter writer = new BufferedWriter(new FileWriter(filenameString));
		writer.write(jsonString);
		writer.close();

	}
}

package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

public class FileUtil {

public static void saveObject(String filenameString, Object object) {

try {

FileOutputStream fo = new FileOutputStream(new File(filenameString));

ObjectOutputStream oo = new ObjectOutputStream(fo);

oo.writeObject(object);

oo.close();

fo.close();

} catch (FileNotFoundException e) {

System.out.println("Datei nicht gefunden");

} catch (IOException e) {

System.out.println("Fehler bei der Initialisierung des Streams");

}

public static Object loadObject(String filenameString) {

Object object = null;

try {

FileInputStream fi = new FileInputStream(new File(filenameString));

ObjectInputStream oi = new ObjectInputStream(fi);

object = (Object) oi.readObject();

oi.close();

fi.close();

} catch (FileNotFoundException e) {

System.out.println("Datei nicht gefunden");

} catch (IOException e) {

System.out.println("Fehler bei der Initialisierung des Streams");

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

return object;

}

public static void saveJsonFile(String filenameString, String jsonString) throws IOException {

BufferedWriter writer = new BufferedWriter(new FileWriter(filenameString));

writer.write(jsonString);

writer.close();

}

Die StringUtil-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.security.*;
import java.util.ArrayList;
import java.util.Base64;
import com.google.gson.GsonBuilder;
import java.io.UnsupportedEncodingException;
import java.util.List;

public class StringUtil {

    public static String generateSha256(String input) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] hash = digest.digest(input.getBytes("UTF-8"));
            StringBuilder hexString = new StringBuilder();
            for (int i = 0; i < hash.length; i++) {
                String hex = Integer.toHexString(0xff & hash[i]);
                if (hex.length() == 1) {
                    hexString.append('0');
                }
                hexString.append(hex);
            }
            return hexString.toString();
        } catch (UnsupportedEncodingException | NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    public static byte[] generateECDSASig(PrivateKey privateKey, String input) {
        Signature dsa;
        byte[] output = new byte[0];
        try {
        	dsa = Signature.getInstance("SHA256withECDSA");
            dsa.initSign(privateKey);
            byte[] strByte = input.getBytes();
            dsa.update(strByte);
            byte[] realSig = dsa.sign();
            output = realSig;
        } catch (InvalidKeyException | NoSuchAlgorithmException | SignatureException e) {
            throw new RuntimeException(e);
        }
        return output;
    }
   
    public static boolean verifyECDSASig(PublicKey publicKey, String data, byte[] signature) {
        try {
        	Signature ecdsaVerify = Signature.getInstance("SHA256withECDSA");
            ecdsaVerify.initVerify(publicKey);
            ecdsaVerify.update(data.getBytes());
            return ecdsaVerify.verify(signature);
        } catch (InvalidKeyException | NoSuchAlgorithmException | SignatureException e) {
            throw new RuntimeException(e);
        }
    }

    public static String getJson(Object o) {
        return new GsonBuilder().setPrettyPrinting().create().toJson(o);
    }

    public static String getDifficultyString(int difficulty, String merkleRoot) { 
        String s = "";
        for(char c : merkleRoot.toCharArray()) {
            if(Character.isDigit(c)) s = s + c;
        }
        if(s.equals("") || s.length() <= 5 ) s = "0123456789";
        String ret = "";
        for(int i = 1; i <= difficulty; i++) {
            int n = difficulty * i;
            while(n >= s.length()) {
                n = (n - s.length()) + i;
            }
            if(n < 0) n = 0;
            ret = ret + s.substring(n, n + 1);
        }
        return ret;
    }

    public static String getStringFromKey(Key key) {
        return Base64.getEncoder().encodeToString(key.getEncoded());
    }
    
    public static String getMerkleRoot(ArrayList<Transaction> transactions) {
        int count = transactions.size();
        List<String> previousTreeLayer = new ArrayList<>();
        for (Transaction transaction : transactions) {
            previousTreeLayer.add(transaction.transactionId);
        }
        List<String> treeLayer = previousTreeLayer;
        while (count > 1) {
            treeLayer = new ArrayList<>();
            for (int i = 1; i < previousTreeLayer.size(); i += 2) {
                treeLayer.add(generateSha256(previousTreeLayer.get(i - 1) + previousTreeLayer.get(i)));
            }
            count = treeLayer.size();
            previousTreeLayer = treeLayer;
        }
        String merkleRoot = (treeLayer.size() == 1) ? treeLayer.get(0) : "";
        return merkleRoot;
    }
}

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package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.security.*;

import java.util.ArrayList;

import java.util.Base64;

import com.google.gson.GsonBuilder;

import java.io.UnsupportedEncodingException;

import java.util.List;

public class StringUtil {

public static String generateSha256(String input) {

try {

MessageDigest digest = MessageDigest.getInstance("SHA-256");

byte[] hash = digest.digest(input.getBytes("UTF-8"));

StringBuilder hexString = new StringBuilder();

for (int i = 0; i < hash.length; i++) {

String hex = Integer.toHexString(0xff & hash[i]);

if (hex.length() == 1) {

hexString.append('0');

}

hexString.append(hex);

}

return hexString.toString();

} catch (UnsupportedEncodingException | NoSuchAlgorithmException e) {

throw new RuntimeException(e);

}

public static byte[] generateECDSASig(PrivateKey privateKey, String input) {

Signature dsa;

byte[] output = new byte[0];

try {

dsa = Signature.getInstance("SHA256withECDSA");

dsa.initSign(privateKey);

byte[] strByte = input.getBytes();

dsa.update(strByte);

byte[] realSig = dsa.sign();

output = realSig;

} catch (InvalidKeyException | NoSuchAlgorithmException | SignatureException e) {

throw new RuntimeException(e);

}

return output;

}

public static boolean verifyECDSASig(PublicKey publicKey, String data, byte[] signature) {

try {

Signature ecdsaVerify = Signature.getInstance("SHA256withECDSA");

ecdsaVerify.initVerify(publicKey);

ecdsaVerify.update(data.getBytes());

return ecdsaVerify.verify(signature);

} catch (InvalidKeyException | NoSuchAlgorithmException | SignatureException e) {

throw new RuntimeException(e);

}

public static String getJson(Object o) {

return new GsonBuilder().setPrettyPrinting().create().toJson(o);

}

public static String getDifficultyString(int difficulty, String merkleRoot) {

String s = "";

for(char c : merkleRoot.toCharArray()) {

if(Character.isDigit(c)) s = s + c;

}

if(s.equals("") || s.length() <= 5 ) s = "0123456789";

String ret = "";

for(int i = 1; i <= difficulty; i++) {

int n = difficulty * i;

while(n >= s.length()) {

n = (n - s.length()) + i;

}

if(n < 0) n = 0;

ret = ret + s.substring(n, n + 1);

}

return ret;

}

public static String getStringFromKey(Key key) {

return Base64.getEncoder().encodeToString(key.getEncoded());

}

public static String getMerkleRoot(ArrayList<Transaction> transactions) {

int count = transactions.size();

List<String> previousTreeLayer = new ArrayList<>();

for (Transaction transaction : transactions) {

previousTreeLayer.add(transaction.transactionId);

}

List<String> treeLayer = previousTreeLayer;

while (count > 1) {

treeLayer = new ArrayList<>();

for (int i = 1; i < previousTreeLayer.size(); i += 2) {

treeLayer.add(generateSha256(previousTreeLayer.get(i - 1) + previousTreeLayer.get(i)));

}

count = treeLayer.size();

previousTreeLayer = treeLayer;

}

String merkleRoot = (treeLayer.size() == 1) ? treeLayer.get(0) : "";

return merkleRoot;

}

Die Transaction-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.io.Serializable;
import java.security.*;
import java.util.ArrayList;

public class Transaction implements Serializable{

	private static final long serialVersionUID = -3795222285878701219L;
	public String transactionId;
    public PublicKey sender;
    public PublicKey recipient;
    public float value;
    public byte[] signature;

    public boolean asReward = false; 
    
    public ArrayList<TransactionInput> inputs = new ArrayList<>();
    public ArrayList<TransactionOutput> outputs = new ArrayList<>();

    private static int sequence = 0;

    public Transaction(PublicKey from, PublicKey to, float value, ArrayList<TransactionInput> inputs) {
        this.sender = from;
        this.recipient = to;
        this.value = value;
        this.inputs = inputs;
    }

    public boolean processTransaction() {
        if (verifySignature() == false) {
            System.out.println("# Transaktion - Die Signatur ist nicht korrekt");
            return false;
        }
        for (TransactionInput i : inputs) {
            i.UTXO = JavaCryptoCoin.UTXOs.get(i.transactionOutputId);
        }
        if (getInputsValue() < JavaCryptoCoin.minimumTransaction) {
            System.out.println("# Transaktion Der Input ist zu gering: " + getInputsValue());
            System.out.println("# Bitte geben Sie einen Betrag groesser als " + JavaCryptoCoin.minimumTransaction + " ein.");
            return false;
        }
        float leftOver = getInputsValue() - value; //get value of inputs then the left over change:
        transactionId = calculateHash();
        outputs.add(new TransactionOutput(this.recipient, value, transactionId)); //send value to recipient
        outputs.add(new TransactionOutput(this.sender, leftOver, transactionId)); //send the left over 'change' back to sender		
        for (TransactionOutput o : outputs) {
        	JavaCryptoCoin.UTXOs.put(o.id, o);
        }
        for (TransactionInput i : inputs) {
            if (i.UTXO == null) {
                continue;            }
            JavaCryptoCoin.UTXOs.remove(i.UTXO.id);
        }
        return true;
    }

    public float getInputsValue() {
        float total = 0;
        for (TransactionInput i : inputs) {
            if (i.UTXO == null) {
                continue;
            }
            total += i.UTXO.value;
        }
        return total;
    }

    public void generateSignature(PrivateKey privateKey) {
        String data = StringUtil.getStringFromKey(sender) + StringUtil.getStringFromKey(recipient) + Float.toString(value);
        signature = StringUtil.generateECDSASig(privateKey, data);
    }

    public boolean verifySignature() {
        String data = StringUtil.getStringFromKey(sender) + StringUtil.getStringFromKey(recipient) + Float.toString(value);
        return StringUtil.verifyECDSASig(sender, data, signature);
    }

    public float getOutputsValue() {
        float total = 0;
        for (TransactionOutput o : outputs) {
            total += o.value;
        }
        return total;
    }

    public String calculateHash() {
        sequence++;
        return StringUtil.generateSha256(
                StringUtil.getStringFromKey(sender)
                + StringUtil.getStringFromKey(recipient)
                + Float.toString(value) + sequence
        );
    }
}

100

package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.io.Serializable;

import java.security.*;

import java.util.ArrayList;

public class Transaction implements Serializable{

private static final long serialVersionUID = -3795222285878701219L;

public String transactionId;

public PublicKey sender;

public PublicKey recipient;

public float value;

public byte[] signature;

public boolean asReward = false;

public ArrayList<TransactionInput> inputs = new ArrayList<>();

public ArrayList<TransactionOutput> outputs = new ArrayList<>();

private static int sequence = 0;

public Transaction(PublicKey from, PublicKey to, float value, ArrayList<TransactionInput> inputs) {

this.sender = from;

this.recipient = to;

this.value = value;

this.inputs = inputs;

}

public boolean processTransaction() {

if (verifySignature() == false) {

System.out.println("# Transaktion - Die Signatur ist nicht korrekt");

return false;

}

for (TransactionInput i : inputs) {

i.UTXO = JavaCryptoCoin.UTXOs.get(i.transactionOutputId);

}

if (getInputsValue() < JavaCryptoCoin.minimumTransaction) {

System.out.println("# Transaktion Der Input ist zu gering: " + getInputsValue());

System.out.println("# Bitte geben Sie einen Betrag groesser als " + JavaCryptoCoin.minimumTransaction + " ein.");

return false;

}

float leftOver = getInputsValue() - value; //get value of inputs then the left over change:

transactionId = calculateHash();

outputs.add(new TransactionOutput(this.recipient, value, transactionId)); //send value to recipient

outputs.add(new TransactionOutput(this.sender, leftOver, transactionId)); //send the left over 'change' back to sender

for (TransactionOutput o : outputs) {

JavaCryptoCoin.UTXOs.put(o.id, o);

}

for (TransactionInput i : inputs) {

if (i.UTXO == null) {

continue; }

JavaCryptoCoin.UTXOs.remove(i.UTXO.id);

}

return true;

}

public float getInputsValue() {

float total = 0;

for (TransactionInput i : inputs) {

if (i.UTXO == null) {

continue;

}

total += i.UTXO.value;

}

return total;

}

public void generateSignature(PrivateKey privateKey) {

String data = StringUtil.getStringFromKey(sender) + StringUtil.getStringFromKey(recipient) + Float.toString(value);

signature = StringUtil.generateECDSASig(privateKey, data);

}

public boolean verifySignature() {

String data = StringUtil.getStringFromKey(sender) + StringUtil.getStringFromKey(recipient) + Float.toString(value);

return StringUtil.verifyECDSASig(sender, data, signature);

}

public float getOutputsValue() {

float total = 0;

for (TransactionOutput o : outputs) {

total += o.value;

}

return total;

}

public String calculateHash() {

sequence++;

return StringUtil.generateSha256(

StringUtil.getStringFromKey(sender)

+ StringUtil.getStringFromKey(recipient)

+ Float.toString(value) + sequence

);

}

Die TransactionInput-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.io.Serializable;

public class TransactionInput implements Serializable{

	private static final long serialVersionUID = -6643746839251237698L;
	public String transactionOutputId;
    public TransactionOutput UTXO;

    public TransactionInput(String transactionOutputId) {
        this.transactionOutputId = transactionOutputId;
    }
}

package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.io.Serializable;

public class TransactionInput implements Serializable{

private static final long serialVersionUID = -6643746839251237698L;

public String transactionOutputId;

public TransactionOutput UTXO;

public TransactionInput(String transactionOutputId) {

this.transactionOutputId = transactionOutputId;

}

Die TransactionOutput-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.io.Serializable;
import java.security.PublicKey;

public class TransactionOutput implements Serializable{

	private static final long serialVersionUID = 7902714355455361435L;
	public String id;
	public PublicKey recipient;
	public float value;
	public String parentTransactionId;

	public TransactionOutput(PublicKey recipient, float value, String parentTransactionId) {
		this.recipient = recipient;
		this.value = value;
		this.parentTransactionId = parentTransactionId;
		this.id = StringUtil
				.generateSha256(StringUtil.getStringFromKey(recipient) + Float.toString(value) + parentTransactionId);
	}

	public boolean isMine(PublicKey publicKey) {
		return (publicKey.equals(recipient));
	}
}

package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.io.Serializable;

import java.security.PublicKey;

public class TransactionOutput implements Serializable{

private static final long serialVersionUID = 7902714355455361435L;

public String id;

public PublicKey recipient;

public float value;

public String parentTransactionId;

public TransactionOutput(PublicKey recipient, float value, String parentTransactionId) {

this.recipient = recipient;

this.value = value;

this.parentTransactionId = parentTransactionId;

this.id = StringUtil

.generateSha256(StringUtil.getStringFromKey(recipient) + Float.toString(value) + parentTransactionId);

}

public boolean isMine(PublicKey publicKey) {

return (publicKey.equals(recipient));

}

Die Wallet-Klasse:

package net.bplaced.javacrypto.blockchain.step9;

/*
* Diese Klasse gehört zu JavaCryptoCoin.java
* This class belongs to JavaCryptoCoin.java
*/

import java.io.Serializable;
import java.security.*;
import java.security.spec.ECGenParameterSpec;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

public class Wallet implements Serializable{

	private static final long serialVersionUID = 3090822928966119493L;
	public PrivateKey privateKey;
    public PublicKey publicKey;
    public HashMap<String, TransactionOutput> UTXOs = new HashMap<>();

    public Wallet() {
        generateKeyPair();
    }

    public void generateKeyPair() {
        try {
        	// secp192r1 [NIST P-192, X9.62 prime192v1] (1.2.840.10045.3.1.1)
        	// secp224k1 (1.3.132.0.32)
        	// secp224r1 [NIST P-224] (1.3.132.0.33)
        	// secp256k1 (1.3.132.0.10)
        	// secp256r1 [NIST P-256, X9.62 prime256v1] (1.2.840.10045.3.1.7)
        	KeyPairGenerator keypairGenerator = KeyPairGenerator.getInstance("EC", "SunEC");
    		// ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp192r1"); 
        	ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp256r1");
    		keypairGenerator.initialize(ecSpec, new SecureRandom());
    		KeyPair keyPair = keypairGenerator.genKeyPair();
            privateKey = keyPair.getPrivate();
            publicKey = keyPair.getPublic();
        } catch (InvalidAlgorithmParameterException | NoSuchAlgorithmException | NoSuchProviderException e) {
            throw new RuntimeException(e);
        }
    }

    public float getBalance() {
        float total = 0;
        for (Map.Entry<String, TransactionOutput> item : JavaCryptoCoin.UTXOs.entrySet()) {
            TransactionOutput UTXO = item.getValue();
            if (UTXO.isMine(publicKey)) { //if output belongs to me ( if coins belong to me )
                UTXOs.put(UTXO.id, UTXO); //add it to our list of unspent transactions.
                total += UTXO.value;
            }
        }
        return total;
    }
        
    public Transaction sendFunds(PublicKey _recipient, float value) {
        if (getBalance() < value) {
            System.out.println("# Das Guthaben ist zu gering um die Transaktion auszuführen, die Transaktion wurde abgebrochen.");
            System.out.println("# Diese Transaktion scheitert: Empfänger:" + _recipient + "\n  Überweisungsbetrag:" + value);
            return null;
        }
        ArrayList<TransactionInput> inputs = new ArrayList<>();
        float total = 0;
        for (Map.Entry<String, TransactionOutput> item : UTXOs.entrySet()) {
            TransactionOutput UTXO = item.getValue();
            total += UTXO.value;
            inputs.add(new TransactionInput(UTXO.id));
            if (total > value) {
                break;
            }
        }
        Transaction newTransaction = new Transaction(publicKey, _recipient, value, inputs);
        newTransaction.generateSignature(privateKey);
        for (TransactionInput input : inputs) {
            UTXOs.remove(input.transactionOutputId);
        }
        return newTransaction;
    }
}

package net.bplaced.javacrypto.blockchain.step9;

* Diese Klasse gehört zu JavaCryptoCoin.java

* This class belongs to JavaCryptoCoin.java

import java.io.Serializable;

import java.security.*;

import java.security.spec.ECGenParameterSpec;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Map;

public class Wallet implements Serializable{

private static final long serialVersionUID = 3090822928966119493L;

public PrivateKey privateKey;

public PublicKey publicKey;

public HashMap<String, TransactionOutput> UTXOs = new HashMap<>();

public Wallet() {

generateKeyPair();

}

public void generateKeyPair() {

try {

// secp192r1 [NIST P-192, X9.62 prime192v1] (1.2.840.10045.3.1.1)

// secp224k1 (1.3.132.0.32)

// secp224r1 [NIST P-224] (1.3.132.0.33)

// secp256k1 (1.3.132.0.10)

// secp256r1 [NIST P-256, X9.62 prime256v1] (1.2.840.10045.3.1.7)

KeyPairGenerator keypairGenerator = KeyPairGenerator.getInstance("EC", "SunEC");

// ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp192r1");

ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp256r1");

keypairGenerator.initialize(ecSpec, new SecureRandom());

KeyPair keyPair = keypairGenerator.genKeyPair();

privateKey = keyPair.getPrivate();

publicKey = keyPair.getPublic();

} catch (InvalidAlgorithmParameterException | NoSuchAlgorithmException | NoSuchProviderException e) {

throw new RuntimeException(e);

}

public float getBalance() {

float total = 0;

for (Map.Entry<String, TransactionOutput> item : JavaCryptoCoin.UTXOs.entrySet()) {

TransactionOutput UTXO = item.getValue();

if (UTXO.isMine(publicKey)) { //if output belongs to me ( if coins belong to me )

UTXOs.put(UTXO.id, UTXO); //add it to our list of unspent transactions.

total += UTXO.value;

}

return total;

}

public Transaction sendFunds(PublicKey _recipient, float value) {

if (getBalance() < value) {

System.out.println("# Das Guthaben ist zu gering um die Transaktion auszuführen, die Transaktion wurde abgebrochen.");

System.out.println("# Diese Transaktion scheitert: Empfänger:" + _recipient + "\n Überweisungsbetrag:" + value);

return null;

}

ArrayList<TransactionInput> inputs = new ArrayList<>();

float total = 0;

for (Map.Entry<String, TransactionOutput> item : UTXOs.entrySet()) {

TransactionOutput UTXO = item.getValue();

total += UTXO.value;

inputs.add(new TransactionInput(UTXO.id));

if (total > value) {

break;

}

Transaction newTransaction = new Transaction(publicKey, _recipient, value, inputs);

newTransaction.generateSignature(privateKey);

for (TransactionInput input : inputs) {

UTXOs.remove(input.transactionOutputId);

}

return newTransaction;

}

Hier geht es zurück zum Haupt-Teil 9: I09 Der JavaCryptoCoin komplett

Alle Quellcodes zur Blockchain findet Ihr zum Download in meinem Github-Repository, welches Ihr über diesen Link erreicht: https://github.com/java-crypto/I-Blockchain. Alle Programme sind sowohl unter Java 8 als auch unter Java 11 lauffähig.

Die Lizenz zum obigen Beispiel findet Ihr auf der eigenen Lizenz-Seite.

Letzte Aktualisierung: 15.06.2019