▁D amm , ▁Hugo ▁Koch ▁and ▁Arthur ▁Sch erb ius . ▁ ▁In ▁the ▁United ▁States ▁Edward ▁Hugh ▁He bern ▁built ▁a ▁rot or ▁machine ▁using ▁a ▁single ▁rot or ▁in ▁ 1 9 1 7 . ▁He ▁became ▁convinced ▁he ▁would ▁get ▁rich ▁s elling ▁such ▁a ▁system ▁to ▁the ▁military , ▁the ▁He bern ▁Rot or ▁Machine , ▁and ▁produced ▁a ▁series ▁of ▁different ▁machines ▁with ▁one ▁to ▁five ▁rot ors . ▁His ▁success ▁was ▁limited , ▁however , ▁and ▁he ▁went ▁bank rupt ▁in ▁the ▁ 1 9 2 0 s . ▁He ▁sold ▁a ▁small ▁number ▁of ▁machines ▁to ▁the ▁US ▁Navy ▁in ▁ 1 9 3 1 . ▁ ▁In ▁He bern ' s ▁machines ▁the ▁rot ors ▁could ▁be ▁opened ▁up ▁and ▁the ▁w iring ▁changed ▁in ▁a ▁few ▁minutes , ▁so ▁a ▁single ▁mass - produ ced ▁system ▁could ▁be ▁sold ▁to ▁a ▁number ▁of ▁users ▁who ▁would ▁then ▁produce ▁their ▁own ▁rot or ▁key ing . ▁Dec ryption ▁consisted ▁of ▁taking ▁out ▁the ▁rot or ( s ) ▁and ▁turning ▁them ▁around ▁to ▁reverse ▁the ▁circuit ry . ▁Un known ▁to ▁He bern , ▁William ▁F . ▁Fried man ▁of ▁the ▁US ▁Army ' s ▁S IS ▁prompt ly ▁demonstrated ▁a ▁f law ▁in ▁the ▁system ▁that ▁allowed ▁the ▁ci ph ers ▁from ▁it , ▁and ▁from ▁any ▁machine ▁with ▁similar ▁design ▁features , ▁to ▁be ▁crack ed ▁with ▁enough ▁work . ▁ ▁Another ▁early ▁rot or ▁machine ▁invent or ▁was ▁Dutch man ▁Hugo ▁Koch