Black holes evolve by evaporation of their event horizon. While this process is believed to be unitary, there is no consensus on the recovery of information in black hole entropy. A missing link is a unit of information in black hole evaporation. Distinct from Hawking radiation, we identify evaporation in entangled pairs by $\mathbb{P}^2$ topology of the event horizon consistent with the Bekenstein-Hawking entropy in a uniformly spaced horizon area, where $k_B$ denotes the Boltzmann constant. It derives by continuation of $\mathbb{P}^2$ in Rindler spacetime prior to gravitational collapse, subject to a tight correlation of the fundamental frequency of Quasi-Normal-Mode (QNM) ringing in gravitational and electromagnetic radiation. Information extraction from entangled pairs by detecting one over the surface spanned by three faces of a large cube carries a unit of information of $2\log3$ upon including measurement of spin.

5 pages, 2 figures, updated from KPS 70th Anniversary and 2022 Fall Meeting, Busan, South Korea, Oct 19-21, 2022 (Session Field and String Theory, Part B2.01)