Re: an example of "double send" mitigation in practice

On 4 June 2015 at 18:03, David Nicol <davidnicol@gmail.com> wrote:

>
>
> On Mon, Jun 1, 2015 at 8:30 AM, David Nicol <davidnicol@gmail.com> wrote:
>
>>
>>
>> And yes, double-sent e-mail is a problem, but it is a mild one, and how a
>> MUA (or listserv software) deals with receiving the same message both
>> directly and from a mailing list (as this message will be delivered, to
>> four recipients who are on the mailing list it is also sent to) is a user
>> experience design choice, as there isn't that much riding on it. For
>> instance, listserv software might not bother to deliver to a recipient
>> listed in the message headers, I think that's a fair optimization listserv
>> software may do.
>>
>
> Found it! I knew I'd seen that option somewhere and it is in subscription
> settings with GNU Mailman. Here's the relevant section from the GNU Mailman
> subscriber manual, which is organized as a FAQ list. So as I was saying, *e-mail
> does have a situation analogous to double-spend*, complete with
> implemented mitigation measures. To give paranoids something else to worry
> about, *this feature makes it possible for a capable and sneaky message
> originator to select mailing list members who have the feature enabled for
> exclusion from distribution of a message*, as listservs have no mechanism
> available for verifying that listing as a To: or Cc: recipient genuinely
> represents that the message was in fact served directly to the alleged
> recipients.
>
> 7.2 How can I avoid getting duplicate messages? (duplicates option)
>
>    Mailman can't completely stop you from getting duplicate messages, but
>    it can help. One common reason people get multiple copies of a mail is
>    that the sender has used a "group reply" function to send mail to both
>    the list and some number of individuals. If you want to avoid getting
>    these messages, Mailman can be set to check and see if you are in the
>    To: or CC: lines of the message. If your address appears there, then
>    Mailman can be told not to deliver another copy to you.
>
> Ive come to the conclusion that double spend is a feature not a bug.
Example:  when I use a credit card I spend money from my account to
another.  But loyalty points are double spent from another account.
There's many examples of this.  When I play tennis I score points which I
cant spend on, but I can also win money playing tennis.  When you have
trust, the double spend issue becomes a feature, not a problem.  It's still
important to solve double spend in trustless environments.