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The simple Caesar-cypher encryption that replaces each Unicode character with the one 0x8000 places forward or back along the alphabet,
so that "The butler did it!" becomes "籝籱籮 籫籾籽籵籮类 籭籲籭 籲籽簪"
It is used to enclose the text in a sealed wrapper that the reader must choose to open - e.g. for posting things that might offend some readers, or spoilers.
While rot13 is the self-inverse for a 26-character system, and rot47 for ANSI, the Basic Multilingual Plane of Unicode requires rot32768 (or 8000 in hex) for a reciprical cypher -- meaning that executing it twice restores the original text.
It also bypasses 32 control characters, technically making it rotFFE0, sometimes with an additional offset.
In Back To The Future II, Marty McFly travels to 21 OCT 2015. As of today, we have only one week left for the franchise to feature time-travel into the future. After that, all the BTTF films will feature Marty travelling into the past from our perspective. ―ask_if_im_pikachu, Oct 2015