AWS加密：无法打开下载的aws s3存储桶加密文件；文件损坏

Question

我已将客户端加密用于s3存储桶。我在Java Spring Boot中使用它。 这是我的s3存储桶配置代码：

@Bean
public AmazonS3 s3client() throws Exception {

BasicAWSCredentials awsCreds = new BasicAWSCredentials(awsId, awsKey);

KeyGenerator symKeyGenerator = KeyGenerator.getInstance("AES");
symKeyGenerator.init(256);
SecretKey symKey = symKeyGenerator.generateKey();

saveSymmetricKey(masterKeyDir, masterKeyName, symKey);
symKey = loadSymmetricAESKey(masterKeyDir, masterKeyName, "AES");
AmazonS3 s3EncryptionClient = null;
try{
  EncryptionMaterials encryptionMaterials = new EncryptionMaterials(symKey);
  s3EncryptionClient = AmazonS3EncryptionClientBuilder.standard()
          .withCredentials(new AWSStaticCredentialsProvider(awsCreds))
          .withEncryptionMaterials(new StaticEncryptionMaterialsProvider(encryptionMaterials))
          .withRegion(region)
          .build();
}catch (Exception e){
  e.printStackTrace();
}

return s3EncryptionClient;}

这是我的服务班级：

public void saveFile(MultipartFile file) throws NoSuchAlgorithmException, IOException {

    try {
        File convFile = convertMultiPartToFile(file);
        logger.info("===================== Upload start =====================");
        s3client.putObject(new PutObjectRequest(bucketName, file.getOriginalFilename(), FileUtils.openInputStream(convFile), new ObjectMetadata()));
        logger.info("===================== Upload File - Done! =====================");

    } catch (AmazonServiceException ase) {
        logger.info("Caught an AmazonServiceException from PUT requests, rejected reasons:");
        logger.info("Error Message:    " + ase.getMessage());
        logger.info("HTTP Status Code: " + ase.getStatusCode());
        logger.info("AWS Error Code:   " + ase.getErrorCode());
        logger.info("Error Type:       " + ase.getErrorType());
        logger.info("Request ID:       " + ase.getRequestId());
        ase.printStackTrace();
    } catch (AmazonClientException ace) {
        logger.info("Caught an AmazonClientException: ");
        logger.info("Error Message: " + ace.getMessage());
        ace.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

public void downloadFile() {
    java.util.Date expiration = new java.util.Date();
    long expTimeMillis = expiration.getTime();
    expTimeMillis += 1000*60*60;
    expiration.setTime(expTimeMillis);
    GeneratePresignedUrlRequest generatePresignedUrlRequest = new GeneratePresignedUrlRequest(bucketName, objectKey).withMethod(HttpMethod.GET).withExpiration(expiration);
    URL url = s3client.generatePresignedUrl(generatePresignedUrlRequest);
    System.out.println(url.toString());
}

这是我使用预签名的URL打开下载的文件时得到的错误：

无法加载图像。解释JPEG图像文件时出错。