DesEncrypter.java Source code

Introduction

Here is the source code for DesEncrypter.java

Source

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;

class DesEncrypter {
    byte[] buf = new byte[1024];
    Cipher ecipher;
    Cipher dcipher;

    DesEncrypter(SecretKey key) throws Exception {
        byte[] iv = new byte[] { (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A };
        AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
        ecipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        dcipher = Cipher.getInstance("DES/CBC/PKCS5Padding");

        ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
        dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
    }

    public void encrypt(InputStream in, OutputStream out) throws Exception {
        out = new CipherOutputStream(out, ecipher);

        int numRead = 0;
        while ((numRead = in.read(buf)) >= 0) {
            out.write(buf, 0, numRead);
        }
        out.close();
    }

    public void decrypt(InputStream in, OutputStream out) throws Exception {
        in = new CipherInputStream(in, dcipher);

        int numRead = 0;
        while ((numRead = in.read(buf)) >= 0) {
            out.write(buf, 0, numRead);
        }
        out.close();
    }
}

public class Main {
    public static void main(String[] argv) throws Exception {
        SecretKey key = KeyGenerator.getInstance("DES").generateKey();
        DesEncrypter encrypter = new DesEncrypter(key);
        encrypter.encrypt(new FileInputStream("cleartext1"), new FileOutputStream("ciphertext"));
        encrypter.decrypt(new FileInputStream("ciphertext"), new FileOutputStream("cleartext2"));
    }
}