I have a bucket my-bucket-name and I want to grant temporary access to some file.pdf in folder-name. As for default I get next link using boto3:

https://my-bucket-name.s3.amazonaws.com/folder-name/file.pdf?AWSAccessKeyId=<key>&Signature=<signature>&x-amz-security-token=<toke>&Expires=<time>

But also I've got a DNS alias, my.address.com is mapped to my-bucket-name.s3.amazonaws.com. Of course, if I'm using it directly I got SignatureDoesNotMatch from amazon. So I'm using next code to generate pre-signed link:

from botocore.client import Config

kwargs = {}
kwargs['endpoint_url'] = f'https://my.address.com'
kwargs['config'] = Config(s3={'addressing_style': 'path'})

s3_client = boto3.client('s3', **kwargs)
url = s3_client.generate_presigned_url(ClientMethod='get_object',
                                       Params={
                                          'Bucket': 'my-bucket-name',
                                          'Key': 'folder-name/file.pdf'
                                       },
                                       ExpiresIn=URL_EXPIRATION_TIME)

As a result it returns me next link:

https://my.address.com/my-bucket-name/folder-name/file.pdf?AWSAccessKeyId=<key>&Signature=<signature>&x-amz-security-token=<toke>&Expires=<time>

There are two problems with this:

• I don't want to expose my bucket name, so my-bucket-name/ should be ommited
• This link doesn't work, I'm getting

<Code>SignatureDoesNotMatch</Code>
<Message>
The request signature we calculated does not match the signature you provided. Check your key and signing method.
</Message>

Those these are the questions:

1. Is it possible to achieve a workable link without exposing bucket name?
2. I've already read something about that custom domains are only possible for HTTP, not HTTPS access, is it true? What should I do in this case?
3. The DNS alias wasn't made by me, so I'm not sure if it works or is set up correctly, what should I check/ask to verify that it will be working for s3?

Currently I'm a bit lost in Amazon docs. Also I'm new to all this AWS stuff.