How to use the Blowfish algorithm to encrypt 64-bit blocks with a constant key

The Java sample program below shows how to encrypt 64-bit data blocks with Blowfish.

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.util.Arrays;

public class TestBlowfish {

static public void main (String args[]) throws Exception {
   byte[] key = {0x11,0x22,0x33,0x44};
   byte[] plainData = {0x55,(byte)0xaa,0x12,0x34,0x56,0x78,(byte)0x9a,(byte)0xbc};
   byte[] encryptedData = new byte[8];
   encrypt (plainData,encryptedData,key);
   byte[] decryptedData = new byte[8];
   decrypt (encryptedData,decryptedData,key);
   if (!Arrays.equals(plainData,decryptedData)) throw new Exception ("Decrypted data not equal.");
   System.out.println ("ok"); }

private static void encrypt (byte[] input, byte[] output, byte[] key) throws Exception {
   crypt (Cipher.ENCRYPT_MODE,input,output,key); }

private static void decrypt (byte[] input, byte[] output, byte[] key) throws Exception {
   crypt (Cipher.DECRYPT_MODE,input,output,key); }

private static void crypt (int opmode, byte[] input, byte[] output, byte[] key) throws Exception {
   Cipher cipher = Cipher.getInstance("Blowfish/ECB/NoPadding");
   SecretKeySpec keySpec = new SecretKeySpec(key,"Blowfish");
   cipher.init (opmode, keySpec);
   cipher.doFinal (input,0,input.length,output); }

}

Author: Christian d'Heureuse (www.source-code.biz, www.inventec.ch/chdh)
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