[OSM-talk-be] Wallonie picarde à vélo / ODBL compatible ?

[Ruben Maes]

2015-05-29 20:22 GMT+02:00 André Pirard <A.Pirard.Papou at gmail.com>:
> On 2015-05-29 15:50, Marc Gemis wrote :
>> totally of topic,
>
> Not off topic. It was part of a reply to a remark that your usual incomplete
> quotation does not show.
>
I think he meant that his own statement that followed was off topic ;)

>> but the right way to do this is to only send the letter (folded and address
>> on the same paper as the text) and not put it in an envelope.
>
> And how does that prevent someone to claim that he received an empty
> envelope?
If you send only one piece, and the other party have confirmed they
received something, that something must be that one piece you sent,
must it not?

> while I am explaining that e-mail is better
I too have always had serious doubts about documents on paper. A
signature? Come on, even a child can spoof that.
But e-mail does not guarantee you anything more than a regular signed
letter by regular post. It is way too easy to spoof a sender(1) and it
also possible to obstruct the delivery of a message.
There are ways to implement undeniability of course(2), but they are
not what you do when you send a simple e-mail.
>

(1) Just like writing a different sender on the back of an envelope
you send. Although in the latest years, more and more e-mail providers
are taking steps to prevent this, not wholly unsuccesful.
(2) <totallyofftopic> On a business-to-business level undeniability is
usually managed like this IIRC:
    1. You send an encrypted message.
    2. The receiving party decrypts the message, and calculates a hash of it.
    3. It signs this hash using its private key and sends it back to you.
    4. You check the signature of the received hash using the
receiver's public key.
    5. You calculate the hash of your own message, and check whether
it matches with the hash you received back.
    Now you can as good as prove that they received your message
correctly, because the receiver has signed its hash.</totallyofftopic>