This is simply a step of; Instead of dropping all items inside the wreck, they will be inside a box. You can then open it or sell it to someone else, perhaps for a higher price of the contents. A gamble at the discretion of whoever opens the box. There is nothing else involved in this process.

Absolutely no key needed. They are exactly like the boxes acquired through the Shadow of the Serpent / Scope Network event.

Basically the loot goes into this box instead, and you get to open this yourself or can sell it to another player who can pay some ISK to take a gamble at opening the box.

CCP Larrikin also mentioned future possibilities involving the strong box, such as selling back to the NPC Corporation you looted it from, or handing it in for standings rewards. Both are future possibilities we can investigate depending on the feedback we get.

Be careful if you're by yourself, they have sharp edges.