Surely the lady and her beau share intimate secrets that no one else knows. These can be used as shared secrets that can form the basis for any number of schemes. Perhaps simplest is to determine the combination of a combination lock. --ms On 10-May-16 09:39, Fred Lunnon wrote:
It doesn't work: the telephone cannot be used to authenticate the sender (though it is still required to inform the postal service indirectly that no key can be expected). The postman in the middle simply exchanges his empty box for the genuine one whenever either is received, until he gets lucky.
I can't see an alternative to some kind of public-key: for example, exchanging unlocked boxes packed with (cheap) unlocked, snap-closing, padlocks without keys (prior to communicating the arrangement over the telephone).
There's a lot to be said for just sticking to dating the girl next door!
Fred Lunnon
On 5/9/16, Fred Lunnon <fred.lunnon@gmail.com> wrote:
I see Victor just beat me to it.
But the penny has just dropped about Diffie-Hellman and "man-in-the-middle" --- Alice and Bob must acknowledge receipt by telephone, otherwise the post office might impersonate each to the other and nab the goodies after all!
WFL
On 5/9/16, Fred Lunnon <fred.lunnon@gmail.com> wrote:
He sends her box and ring, locked with his padlock.
She returns it, double-locked with her padlock.
He unlocks his padlock and resends.
She unlocks her padlock.
Thinks "just as well this wasn't fresh caviar!"
WFL
On 5/9/16, Dave Dyer <ddyer@real-me.net> wrote:
At 10:49 AM 5/9/2016, Brent Meeker wrote:
Send the key first. Only send the box after the key arrives. No, send the box first. If an anonymous locked box won't get through, the whole exercise is pointless. Any attempt to send the key first might alert the authorities to watch for the box. Once the box is safely transferred, as many attempts as necessary can be made to send a key for the box, which is already secure.
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