[Cryptography] How should we encrypt external mail attachments

[Roland C. Dowdeswell]

On Sun, Aug 01, 2021 at 02:59:39PM -0400, John Levine wrote:
>

> My question is what algorithms to use? The file can be anything up to
> several gigabytes so they should be reasonably fast. It's OK if the hash
> and key are fairly large, since a few hundred or even a few thousand
> bytes in a mail message is not a big deal these days.

For very large videos, it might be interesting to be able to stream
them.  So, perhaps you could define a very simple chunked encoding
where each bit is HMACed separately?

--
    Roland C. Dowdeswell                          https://Imrryr.ORG/