[Cryptography] Comey: targeted ads => plaintext access

[Henry Baker]

At 07:42 PM 9/15/2015, Benjamin Kreuter wrote:
>> Obviously, any scheme that targets ads based upon the *unencrypted
>> content* of an email must *leak a certain amount of information from
>> that content* -- at least to the ad broker.
>
>This is not necessarily true.  You can imagine a multiparty protocol
>that targets ads based on email plaintexts without revealing information
>about plaintexts to an ad broker, while still ensuring that payments
>occur properly.  It is all theoretical for now and there are a lot of
>complexities and subtle (and not so subtle) assumptions, but at least on
>paper we could do it.

Hmmm...  I'm interested in learning more about how this ad scheme
might work.

Nevertheless, if some questionable people were talking about fertilizers
in their emails, and they started getting ads from fertilizer companies,
it might not matter very much if anything else from the emails was
leaked!

I worry enough when the TV shows I happen to like advertise
constipation drugs!