On Thu, Feb 12, 2015 at 9:32 AM, Matt Rice <[email protected]> wrote: > On Thu, Feb 12, 2015 at 3:46 AM, Matt Rice <[email protected]> wrote: >> On Thu, Feb 12, 2015 at 1:22 AM, Matt Oliveri <[email protected]> wrote: >>> I can't figure out why the unsealer sets content to nullObj again >>> after it reads it. Does anyone know? >> >> in the unseal function the first content := nullObj; call seems to be >> there to protect a previously unsealed value by let bar () = ();; >> unseal(bar);; (calling the unsealer with a box that doesn't produce >> the effect) > > *sigh* I think I really butchered trying to explain this... > > so say if you have the box, but not the unsealer, and I have the > unsealer but not the box, > the first prevents us from collaborating, you first calling box() to > produce the effect, me calling unseal(bar) without producing _any_ > effect and retrieving the sealed value.
Yeah, I figured that part out, thanks. >> and I believe the 2nd call is there so that if you can cause someone >> else to cause the effect, you cannot invoke their function that causes >> the effect from within the filledbox () call and take their sealed >> value that you do not have > > I think I failed to explain this well too, by not specifying the > negating effect, > you have a box and thus cause the effect, and unseal (causing the > effect and negating the effect), > > I can unseal but do not have your box, > you are going to allow me to call you, upon which time you will unseal the > box, > and presumably do some computation... Thus I can call you to cause > the effect but not without calling the negating effect before you > return to me. > > this prevents me from calling you to unseal your box, within the > fillbox () call I have passed to my copy of the (same) unsealer, then > reading the contents > and returning it to myself. > > the only way for me to unseal your value is with the ability to cause > the effect without the negating effect from within my copy of the > unsealer Ah I see! Getting someone to unseal while I unseal with a fake box. Tricky. Thank you very much. _______________________________________________ bitc-dev mailing list [email protected] http://www.coyotos.org/mailman/listinfo/bitc-dev
