多线程中的AES + HMAC加密 - Java

Question

我正在开发一个程序来使用AES-256和HMAC加密/解密二进制文件来检查结果.

我的代码基于Java中的AESCrypt实现,但我想修改它以允许多个线程同时完成工作.

我得到原始字节的大小并计算每个线程16字节块的数量,然后我启动线程,其中包含有关应用于读取和写入的偏移量的信息(因为加密文件有一个头,所以offset_write = offset_read + header_length).

当它完成加密时,我通过HMAC传递输出内容(没有标题)以生成校验和.

问题是某些字节在两个线程之间的字节中被破坏.

主要代码:

//..
// Initialization and creation of iv, aesKey
//..

in = new FileInputStream(fromPath);
out = new FileOutputStream(toPath);

//..
// Some code for generate the header and write it to out
//..
double totalBytes = new Long(archivo.length()).doubleValue();
int bloquesHilo = new Double(Math.ceil(totalBytes/(AESCrypt.NUM_THREADS*AESCrypt.BLOCK_SIZE))).intValue();
int offset_write = new Long((out.getChannel()).position()).intValue();

for (int i = 0; i < AESCrypt.NUM_THREADS; i++)
{
    int offset = bloquesHilo*AESCrypt.BLOCK_SIZE*i;
    HiloCrypt hilo = new HiloCrypt(fromPath, toPath, ivSpec, aesKey, offset, offsetInicio, bloquesHilo, this);
    hilo.start();
}

线程代码(类HiloCrypt):公共类HiloCrypt扩展Thread {

    private RandomAccessFile in;
    private RandomAccessFile out;

    private Cipher cipher;
    private Mac hmac;
    private IvParameterSpec ivSpec2;
    private SecretKeySpec aesKey2;

    private Integer num_blocks;
    private Integer offset_read;
    private Integer offset_write;

    private AESCrypt parent;

    public HiloCrypt(String input, String output, IvParameterSpec ivSpec, SecretKeySpec aesKey, Integer offset_thread, Integer offset_write, Integer blocks, AESCrypt parent2) 
    {
        try
        {
                        // If i don't use RandomAccessFile there is a problem copying data
            this.in = new RandomAccessFile(input, "r");
            this.out = new RandomAccessFile(output, "rw");

            int total_offset_write = offset_write + offset_thread;

                        // Adjust the offset for reading and writing 
            this.out.seek(total_offset_write);
            this.in.seek(offset_thread);

            this.ivSpec2 = ivSpec;
            this.aesKey2 = aesKey;

            this.cipher = Cipher.getInstance(AESCrypt.CRYPT_TRANS);
            this.hmac = Mac.getInstance(AESCrypt.HMAC_ALG);

            this.num_blocks = blocks;
            this.offset_read = offset_thread;
            this.offset_write = total_offset_write;
            this.parent = parent2;

        } catch (Exception e)
        {
            System.err.println(e);
            return;
        }
    }


    public void run()
        {
        int len, last,block_counter,total = 0;
        byte[] text = new byte[AESCrypt.BLOCK_SIZE];

        try{
            // Start encryption objects
            this.cipher.init(Cipher.ENCRYPT_MODE, this.aesKey2, this.ivSpec2);
            this.hmac.init(new SecretKeySpec(this.aesKey2.getEncoded(), AESCrypt.HMAC_ALG));

            while ((len = this.in.read(text)) > 0 && block_counter < this.num_blocks) 
            {
                this.cipher.update(text, 0, AESCrypt.BLOCK_SIZE, text);
                this.hmac.update(text);

                // Write the block
                this.out.write(text);

                last = len;
                total+=len;

                block_counter++;
            }

            if (len < 0) // If it's the last block, calculate the HMAC
            {
                last &= 0x0f;
                this.out.write(last);

                this.out.seek(this.offset_write-this.offset_read);

                while ((len = this.out.read(text)) > 0) 
                {
                    this.hmac.update(text);
                }

                // write last block of HMAC
                text=this.hmac.doFinal();
                this.out.write(text);
            }

                        // Close streams
            this.in.close();
            this.out.close();

                        // Code to notify the end of the thread
        }
        catch(Exception e)
        {
            System.err.println("Hola!");
            System.err.println(e);
        }
    }
}

使用此代码,如果我只执行1个线程,加密/解密就完美了,但是有2个以上的线程,线程作业之间的区域中存在字节问题,数据在那里被破坏,校验和也失败.

我试图用线程做这个,因为它比一个线程快2倍,我认为这应该是因为处理而不是访问文件.

作为无关数据,它在MB Air上在43秒内压缩250Mb数据.¿这是个好时光？

Answer 1

AESCrypt 不是线程安全的.您不能使用多个线程.

一般来说,加密代码很少是线程安全的,因为它需要复杂的数学来生成安全输出.AES本身相对较快,如果您需要更快的速度,请考虑垂直缩放或硬件加速器作为第一步.稍后,您可以添加更多服务器以同时加密不同的文件(水平扩展).