如何解密 Java 中的 ByteArrayOutputStream.?

Question

I am trying to decrypt a file downloaded as ByteArrayOutputStream from Azure Storage.

I have a stream of type ByteArrayOutputStream. How can I decrypt it and return decrypted ByteArrayOutputStream.?

I have tried using CipherOutputStream, but I'm not sure how to use it.

Below is the code (snippet) I am using to encrypt the file before uploading

cipher.init(Cipher.ENCRYPT_MODE, key,new IvParameterSpec(INITIALIZATIO_VECTOR.getBytes("UTF-8")));
blob.upload(new CipherInputStream(file.getInputStream(), cipher), file.getSize());

Below is my code:

public ByteArrayOutputStream download(String fileName, Long id) {
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    
    try {
        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding", "SunJCE");
        SecretKeySpec key = new SecretKeySpec(encrypkey.getBytes("UTF-8"), "AES");
        cipher.init(Cipher.DECRYPT_MODE, key,new IvParameterSpec(INITIALIZATIO_VECTOR.getBytes("UTF-8")));
        CipherOutputStream output = null;
          
        container = getBlobClient().getContainerReference("container" + id.toString());
        
        CloudBlockBlob blob = container.getBlockBlobReference(fileName);

        if (blob.exists()) {
            blob.download(os);
            //output = new CipherOutputStream(outputStream, cipher);        
        } else {
            logger.info("File does not exists on azure container");
        }
    } catch (StorageException e) {
        logger.error("StorageException : {}" + e.getLocalizedMessage(), e);
    } catch (Exception e) {
        logger.error("Exception : {}" + e.getLocalizedMessage(), e);
    }
    
    return os;
}

Answer 1

First create the CipherOutputStream , then download the blob into that output:

output = new CipherOutputStream(os, cipher);
blob.download(output);