How to decrypt AWS S3 file during download?

Question

Here is my download code :

 IAmazonS3 client;

            string key = tenant_id + @"/files/" + filename;
            try
            {
                using (client = new AmazonS3Client(Amazon.RegionEndpoint.USEast1))
                {
                    GetObjectRequest request = new GetObjectRequest
                    {
                        BucketName = existingBucketName,
                        Key = key
                    };

                    using (GetObjectResponse response = client.GetObject(request))
                    {
                        string dest = path;
                        if (!File.Exists(dest))
                        {
                            response.WriteResponseStreamToFile(dest);
                        }
                    }
                }
                return true;
            }

I would like to decrypt files during the download process. I've gone through the support docs but unable to proceed. What changes do I need to make in my current code to achieve this ?

Answer 1

It depends on how the file was encrypted. S3 supports client-side encryption and server-side encryption .

If the file is encrypted using server-side encryption, either S3 is managing the keys or you need to provide the key in your request. If the file was encrypted client-side prior to being uploaded to S3 then you must decrypt the downloaded file yourself. In this case check out the AmazonS3EncryptionClient to help make things easier.