Eternal black holes are the ultimate cosmic safes - space - 03 September 2010 - New Scientist

Eternal black holes are the ultimate cosmic safes: Hsu realised that running the process backwards would be equivalent to a black hole forming and then existing in a perfect vacuum, with no Hawking radiation. "It becomes a black hole that's not radiating, which is a very weird thing," Hsu says.

The snag is that to run this process backwards and make the eternal black hole, you would need to send in a precisely crafted burst of radiation as the hole forms. The radiation would have to be "exactly tuned to interfere with the Hawking radiation that would otherwise come out", says Hsu.