Java中用于加密和解密文本文件的密钥

Question

我正在使用 Java 开发一个加密/解密程序。我正在使用一个名为“secret1234”的密钥来加密和解密来自文本文件的消息。该程序使用字符串作为键。但是，我有兴趣使用数字（整数）作为密钥，以便生成随机数。那么，如何修改这个程序，让密钥是整数而不是字符串来加密和解密消息呢？

这是程序：

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class Program {

    public static void main(String[] args) {

        try {
            String key = "secret1234";// This is the key

            FileInputStream fis = new FileInputStream("text.txt");//text.txt is a text file with a short message                                        
            FileOutputStream fos = new FileOutputStream("encryptedText.txt");
            encrypt(key, fis, fos);

            FileInputStream fis2 = new FileInputStream("encryptedText.txt");
            FileOutputStream fos2 = new FileOutputStream("decryptedText.txt");
            decrypt(key, fis2, fos2);

        } catch (Throwable e) {
            e.printStackTrace();
        }

    }

    public static void encrypt(String key, InputStream is, OutputStream os) throws Throwable {
        encryptOrDecrypt(key, Cipher.ENCRYPT_MODE, is, os);
    }

    public static void decrypt(String key, InputStream is, OutputStream os) throws Throwable {
        encryptOrDecrypt(key, Cipher.DECRYPT_MODE, is, os);
    }

    public static void encryptOrDecrypt(String key, int mode, InputStream is, OutputStream os) throws Throwable {

        DESKeySpec dks = new DESKeySpec(key.getBytes());
        SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
        SecretKey desKey = skf.generateSecret(dks);
        Cipher cipher = Cipher.getInstance("DES");

        if (mode == Cipher.ENCRYPT_MODE) {
            cipher.init(Cipher.ENCRYPT_MODE, desKey);
            CipherInputStream cis = new CipherInputStream(is, cipher);
            doCopy(cis, os);
        } else if (mode == Cipher.DECRYPT_MODE) {
            cipher.init(Cipher.DECRYPT_MODE, desKey);
            CipherOutputStream cos = new CipherOutputStream(os, cipher);
            doCopy(is, cos);
        }
    }

    public static void doCopy(InputStream is, OutputStream os) throws IOException {
        byte[] bytes = new byte[64];
        int numBytes;
        while ((numBytes = is.read(bytes)) != -1) {
            os.write(bytes, 0, numBytes);
        }
            os.flush();
            os.close();
            is.close();
    }

}

Answer 1

在您的代码中使用它来生成密钥：

String key = String.valueOf(SecureRandom.getInstance("SHA1PRNG").nextInt());