src/StringUtil.java - master - skirill/blockchain

src/StringUtil.java
78 строк3 KB
K. S
Added Wallet and TransactionInput and -Output
18 июл 2024, 16:03
18 июл 2024, 16:037604be7
import java.lang.foreign.AddressLayout;
import java.security.*;
import java.util.ArrayList;
import java.util.Base64;

public class StringUtil {
    public static String applySha256(String input) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] hash = digest.digest(input.getBytes("UTF-8"));
            StringBuffer hexString = new StringBuffer();
            for (byte b : hash) {
                String hex = Integer.toHexString(0xff & b);
                if (hex.length() == 1) hexString.append('0');
                hexString.append(hex);
            }
            return hexString.toString();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static  byte[] applyECDSASig(PrivateKey privateKey, String input) {
        Signature dsa;
        byte[] output = new byte[0];
        try {
            dsa = Signature.getInstance("ECDSA", "BC");
            dsa.initSign(privateKey);
            byte[] strByte = input.getBytes();
            dsa.update(strByte);
            byte[] realSig = dsa.sign();
            output = realSig;
        }
        catch (Exception e) {
            throw new RuntimeException(e);
        }
        return output;
    }

    public static boolean verifyECDSASig(PublicKey publicKey, String data, byte[] signature) {
        try {
            Signature ecdsaVerify = Signature.getInstance("ECDSA", "BC");
            ecdsaVerify.initVerify(publicKey);
            ecdsaVerify.update(data.getBytes());
            return ecdsaVerify.verify(signature);
        }
        catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static String getStringFromKey(Key key) {
        return Base64.getEncoder().encodeToString(key.getEncoded());
    }
    public static String getDificultyString(int difficulty) {
        return new String(new char[difficulty]).replace('\0', '0');
    }

    public static String getMerleRoot(ArrayList<Transaction> transactions) {
        int count = transactions.size();
        ArrayList<String> previousTreeLayer = new ArrayList<String>();
        for(Transaction transaction : transactions) {
            previousTreeLayer.add(transaction.transactionId);
        }
        ArrayList<String> treeLayer = previousTreeLayer;
        while (count > 1) {
            treeLayer = new ArrayList<String>();
            for(int i = 1; i < previousTreeLayer.size(); i++) {
                treeLayer.add(applySha256(previousTreeLayer.get(i-1) + previousTreeLayer.get(i)));
            }
            count = treeLayer.size();
            previousTreeLayer = treeLayer;
        }
        String merkleRoot = (treeLayer.size() == 1) ? treeLayer.get(0) : "";
        return merkleRoot;
    }

}