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加密要通过Amazon S3发送的大流

amazon-s3 encryption java

menteith · 技术社区 · 6 年前

我想加密流,然后使用amazon s3发送它。我使用的是遗留代码,有两个重要参数:非加密 InputStream 以及它的长度。这很重要,因为amazons3client希望在上传流之前知道流的长度。

加密流不是很困难的任务:

        InputStream in = new FileInputStream("path-to-file");
        KeyGenerator keygen = KeyGenerator.getInstance("AES");
        Key key = keygen.generateKey();

        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, key);

        OutputStream encryptedStream = new ByteArrayOutputStream();
        CipherOutputStream out = new CipherOutputStream(encryptedStream, cipher);
        out.write(in.read());
        out.flush();

        byte[] bytes = ((ByteArrayOutputStream) encryptedStream).toByteArray();
        InputStream encryptedInput = new ByteArrayInputStream(bytes);

然而,这种方法只能用于小文件,因为它们被写入内存中的字节数组。问题是我想加密大文件(>1tb)。我该怎么做?更具体地说,我得到了inputstream,我的工作是返回将由amazon s3使用的加密inputstream。

1 回复 | 直到 6 年前

gagan singh 6 年前

不使用 ByteArrayOutputStream

    InputStream in = new FileInputStream("path-to-file");
    KeyGenerator keygen = KeyGenerator.getInstance("AES");
    Key key = keygen.generateKey();

    Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
    cipher.init(Cipher.ENCRYPT_MODE, key);

    try(CipherOutputStream out = new CipherOutputStream(
            new FileOutputStream(new File("path to enc file")), cipher))
    {
        byte[] buffer = new byte[8192];
        int count;
        while ((count = in.read(buffer)) > 0)
        {
            out.write(buffer, 0, count);
        }
    }

    return new FileInputStream(new File("path to enc file"));

再回答一个流水的问题。

    InputStream in = new FileInputStream("path-to-file");
    KeyGenerator keygen = KeyGenerator.getInstance("AES");
    Key key = keygen.generateKey();

    Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
    cipher.init(Cipher.ENCRYPT_MODE, key);

    PipedOutputStream pout = new PipedOutputStream();
    //write data in a separate thread.
    new Thread(() -> {
        try(CipherOutputStream out = new CipherOutputStream(
                pout, cipher))
        {
            byte[] buffer = new byte[8192];
            int count;
            while ((count = in.read(buffer)) > 0)
            {
                out.write(buffer, 0, count);
            }
        } catch (IOException  e)
        {
            e.printStackTrace();
        }
    }).start();

    return new PipedInputStream(pout);

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