MainClass.java Source code

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Here is the source code for MainClass.java

Source

import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

public class MainClass {
    public static void main(String[] args) throws Exception {
        String password = "password";

        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(1024);
        KeyPair keyPair = keyPairGenerator.genKeyPair();
        String publicKeyFilename = "public";

        byte[] publicKeyBytes = keyPair.getPublic().getEncoded();

        FileOutputStream fos = new FileOutputStream(publicKeyFilename);
        fos.write(publicKeyBytes);
        fos.close();

        String privateKeyFilename = "privateKeyFilename";

        byte[] privateKeyBytes = keyPair.getPrivate().getEncoded();

        byte[] encryptedPrivateKeyBytes = passwordEncrypt(password.toCharArray(), privateKeyBytes);

        fos = new FileOutputStream(privateKeyFilename);
        fos.write(encryptedPrivateKeyBytes);
        fos.close();
    }

    private static byte[] passwordEncrypt(char[] password, byte[] plaintext) throws Exception {
        int MD5_ITERATIONS = 1000;
        byte[] salt = new byte[8];
        SecureRandom random = new SecureRandom();
        random.nextBytes(salt);

        PBEKeySpec keySpec = new PBEKeySpec(password);
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithSHAAndTwofish-CBC");
        SecretKey key = keyFactory.generateSecret(keySpec);
        PBEParameterSpec paramSpec = new PBEParameterSpec(salt, MD5_ITERATIONS);
        Cipher cipher = Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
        cipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);

        byte[] ciphertext = cipher.doFinal(plaintext);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        baos.write(salt);
        baos.write(ciphertext);
        return baos.toByteArray();
    }
}