1. [Imperfect variant of one-time pad] Consider a variant of the one-time pad with message space M = {0,1}", where the key space is K = {0,1}"\1" (i.e., the key space consists of all the n-bit strings except for the all-one string). Show that this cipher is not perfectly secure. (15 points) 1. [Imperfect variant of one-time pad] Consider a variant of the one-time pad with message space M = {0,1}", where the key space is K = {0,1}"\1" (i.e., the key space consists of all the n-bit strings except for the all-one string). Show that this cipher is not perfectly secure. (15 points)