使用AES加密和解密音频/视频文件（128）

Question

我正在编写一个程序，将音频/视频文件发送到服务器，在该服务器上数据被加密并通过套接字发送回客户端。在客户端部分，数据被提取并被解密并存储到另一个文件中。数据也被加密和解密，但解密的文件不能正常播放。

任何人都可以帮忙吗？我的代码如下

服务器：

public class Ser_enc 
    { 
    private static int packet_count; 
    private static int packet_size=1024; 
    public static void main(String args[]) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException 
    { 
    System.out.println("Hi iam server"); 
    ServerSocket ss=new ServerSocket(2001); 
    Socket s=ss.accept(); 

    BufferedReader in=new BufferedReader(new InputStreamReader(s.getInputStream()));//sockin 

    OutputStream pw= s.getOutputStream(); 


    String filename=in.readLine(); 
    System.out.println("The file requested is " +filename); 

    String loc="F://files//source_files//"+filename; 

    File file=new File(loc); 

    if(file.exists()) 
    System.out.println("File found"); 

    File to_b_encf =new File("F:/files/source_files//encryped.mp3"); 

    if(!to_b_encf.exists()) 
    to_b_encf.createNewFile(); 

    System.out.println("encrypting"); 

    Cipher encipher = Cipher.getInstance("AES"); 

    KeyGenerator kgen = KeyGenerator.getInstance("AES"); 

    SecretKey skey = kgen.generateKey();//initiate key 

    encipher.init(Cipher.ENCRYPT_MODE, skey); 

    FileInputStream fsrc=new FileInputStream(loc); 

    FileOutputStream encfile=new FileOutputStream(to_b_encf); 

    CipherInputStream cis = new CipherInputStream(fsrc, encipher); 

    int read; 
    while((read=cis.read())!=-1) 
    { 
     encfile.write(read); 
     encfile.flush(); 
    } 

    BufferedInputStream fsrcread=new BufferedInputStream(new FileInputStream(to_b_encf)); 

    packet_count = (int) Math.ceil((to_b_encf.length()/packet_size)); 
    System.out.println("The number of packets to send is :" +packet_count); 
    for(int i=0;i<=packet_count;i++) 
    { 
    byte[] packet=new byte[packet_size]; 

    fsrcread.read(packet, 0, packet_size); 

    int per=(int)((i*100)/(packet_count)); 

    System.out.println("Transfer " +per +"% done"); 

    pw.write(packet); 
    pw.flush(); 

    } 
    s.close(); 
    pw.close(); 
    cis.close(); 
    encfile.close(); 
    } 
    } 

客户：

public class Cli_dec 
{ 
    private static Socket s; 
    private static int read; 
    public static void main(String args[]) throws UnknownHostException, IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException 
    { 

     s=new Socket("127.0.0.1",2001); 

     PrintWriter out=new PrintWriter(s.getOutputStream()); 

     String fname=JOptionPane.showInputDialog(null); 

     out.write(fname+"\n"); 
     out.flush(); 

     int count; 
     byte[] buf=new byte[100000]; 
     System.out.println("Receiving packets"); 
     File f=new File("F:/files/source_files//decryped.mp3"); 
     FileOutputStream to_b_decf=new FileOutputStream(f); 
     BufferedOutputStream bos=new BufferedOutputStream(to_b_decf); 
     InputStream in1=s.getInputStream(); 

     while((count=in1.read(buf))>0) 
     { 
     bos.write(buf, 0,count); 
     bos.flush(); 
     } 

     File destfile =new File("F:/files/source_files//original.mp3"); 

     if(!destfile.exists()) 
     destfile.createNewFile(); 

     Cipher decipher = Cipher.getInstance("AES");//initiate a cipher for decryption 
     KeyGenerator kgen = KeyGenerator.getInstance("AES"); 
     SecretKey skey = kgen.generateKey();//initiate key 
     decipher.init(Cipher.DECRYPT_MODE, skey);//decrypt the file 

     FileInputStream decf=new FileInputStream(f); 

     System.out.println("decrypting"); 

     CipherInputStream c_decf=new CipherInputStream(decf,decipher); 

     FileOutputStream destf=new FileOutputStream(destfile); 

     CipherOutputStream cout=new CipherOutputStream(destf,decipher); 


     while((read=c_decf.read())!=-1) 
     { 
     cout.write(read); 
     cout.flush(); 
     } 
     c_decf.close(); 
     destf.close(); 
     cout.close(); 
     decf.close(); 
     s.close(); 
} 

} 

Answer 1

你在客户端，生成一个随机密钥使用kgen.generateKey() - 你需要使用服务器和客户端使用相同的密钥，否则你会得到乱码。

accepted answer to this question有一些很好的加密代码，您可以使用 - 使用KeySpec spec = new PBEKeySpec(password, salt, 64, 128);减少迭代计数并使用128位加密而不是256位加密。此代码还使用密码块链接代替电子码本，这是更安全的(see this Wikipedia article for an explanation of cipher modes)。服务器和客户端都需要使用相同的密钥生成代码，以便他们的密钥匹配;除了使用相同的密钥之外，加密器和解密器将需要使用相同的初始化向量（IV），但这不是秘密的（可以以明文形式传输）。

Answer 2

我正在开发应用程序的过程中，像你问的那样，你的代码对我很有帮助。

客户模块中你做了双重解密...我的代码看起来像这样

CipherInputStream c_decf = new CipherInputStream(decf, decipher); 

    FileOutputStream destf = new FileOutputStream(destfile); 

    //CipherOutputStream cout = new CipherOutputStream(destf, decipher); 


    while ((read = c_decf.read()) != -1) { 
     destf.write(read); 
     destf.flush(); 
    } 
    c_decf.close(); 
    destf.close(); 
    // cout.close(); 
    decf.close(); 

只是将其删除，并做了密钥生成的How do i decrypt a file in Android with AES?。代码有效。

感谢您发布此问题。