Information is physical, a founding principle for information science that is among the most characteristic features of our modern day life. In both classical and quantum world, information cannot appear or disappear as governed by conservation laws of physics. This is questioned, however, for a black hole by the so-called “information loss paradox”, which is one of the liveliest questions in physics right now.
Recently, we have presented a resolution to the paradox of black hole information loss [1, 2]. In this talk, we present new insights to the paradox, proving that information conservation is universal for any closed system, including a black hole. We prove the total information encoded in the Hawking radiations is exactly equal to the amount previously considered lost, according to the non-thermal spectrum by Parikh and Wilczek. Thus, the paradox is resolved that denotes a unified theory of quantum gravity may be emerging.
 B. Zhang, Q-Y Cai, L. You and M S Zhan, Hidden messenger revealed in Hawking radiation: A resolution to the paradox of black hole information loss. Phys. Lett. B 675, 98-101 (2009).
 B. Zhang, Q-Y Cai, M S Zhan and L. You, Entropy is conserved in Hawking radiation as tunneling: A revisit of the paradox of black hole information loss. Ann. Phys. (NY) 326 , 350 (2011).