Java Tutorial/Security/Blowfish

A Blowfish example

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import sun.misc.BASE64Encoder;
public final class MainClass {
  public static void main(String[] args) throws Exception {
    KeyGenerator keyGenerator = KeyGenerator.getInstance("Blowfish");
    keyGenerator.init(128);
    Key secretKey = keyGenerator.generateKey();
    Cipher cipherOut = Cipher.getInstance("Blowfish/CFB/NoPadding");
    cipherOut.init(Cipher.ENCRYPT_MODE, secretKey);
    BASE64Encoder encoder = new BASE64Encoder();
    byte iv[] = cipherOut.getIV();
    if (iv != null) {
      System.out.println("Initialization Vector of the Cipher:\n" + encoder.encode(iv));
    }
    FileInputStream fin = new FileInputStream("inputFile.txt");
    FileOutputStream fout = new FileOutputStream("outputFile.txt");
    CipherOutputStream cout = new CipherOutputStream(fout, cipherOut);
    int input = 0;
    while ((input = fin.read()) != -1) {
      cout.write(input);
    }
    fin.close();
    cout.close();
  }
}

Create a Blowfish key, encrypts some text,prints the ciphertext, then decrypts the text

import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
public class MainClass {
  public static void main(String[] args) throws Exception {
    String text = "jexp";
    KeyGenerator keyGenerator = KeyGenerator.getInstance("Blowfish");
    keyGenerator.init(128);
    Key key = keyGenerator.generateKey();
    Cipher cipher = Cipher.getInstance("Blowfish/ECB/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, key);
    byte[] ciphertext = cipher.doFinal(text.getBytes("UTF8"));
    for (int i = 0; i < ciphertext.length; i++) {
      System.out.print(ciphertext[i] + " ");
    }
    cipher.init(Cipher.DECRYPT_MODE, key);
    byte[] decryptedText = cipher.doFinal(ciphertext);
    System.out.println(new String(decryptedText, "UTF8"));
  }
}
//-126 -104 127 -75 -34 -71 -94 -96 jexp

Generate a Blowfish key

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
public class MainClass {
  public static void main(String[] args) throws Exception {
    KeyGenerator keyGenerator = KeyGenerator.getInstance("Blowfish");
    keyGenerator.init(128);
    SecretKey key = keyGenerator.generateKey();
    Cipher cipher = Cipher.getInstance("Blowfish/ECB/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, key);
    
    byte[] cipherText = cipher.doFinal("This is a test.".getBytes("UTF8"));
    
    System.out.println(new String(cipherText));
  }
}