"A major weakness of the system, however, was that no letter could be enciphered to itself." In hindsight this seems like a huge blunder. Even at the time of d

"A major weakness of the system, however, was that no letter could be enciphered to itself." In hindsight this seems like a huge blunder. Even at the time of design it seems that if anyone were to ask the question "should we exclude enciphering "X" as "X" even the most rookie cryptographer would say "Of course not! That's absurd!"