488 lines
17 KiB
Java
488 lines
17 KiB
Java
package de.vanitasvitae.enigmandroid.enigma.rotors;
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/**
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* Rotor super class and inner concrete implementations
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* The rotors were the key feature of the enigma used to scramble up input signals into
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* encrypted signals difficult to predict. The rotors rotated to achieve a poly-alphabetic
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* substitution which was hard to break. Each signal passes the rotor twice. Once in "forward"-
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* direction and once in "backwards"-direction. There was a set of 3 out of 5 rotors inside the
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* enigma machine M4.
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* Copyright (C) 2015 Paul Schaub
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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* @author vanitasvitae
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*/
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public class Rotor
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{
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protected String type;
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protected int number;
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protected Integer[] connections;
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protected Integer[] reversedConnections;
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protected Integer[] turnOverNotches;
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protected int ringSetting;
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protected int rotation;
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/**
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* This constructor is not accessible from outside this class file.
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* Use one of the createRotor* factory methods instead to create concrete Rotors.
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* Note that connections and reversedConnections MUST be of the same size and that
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* neither connections nor reversedConnections respectively MUST have any number between
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* 0 and connections.length-1 only once (ie they represent permutations)
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* @param type type indicator
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* @param connections wiring of the rotor as Integer array
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* @param reversedConnections inverse wiring used to encryptString in the opposite direction
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* (connections[reversedConnections[i]] = i
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* for all i in 0..getRotorSize()-1.
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* @param turnOverNotches Position(s) of the turnover notch(es)
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* @param ringSetting setting of the ring that holds the letters
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* @param rotation rotation of the rotor
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*/
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protected Rotor(String type, int number, Integer[] connections, Integer[] reversedConnections,
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Integer[] turnOverNotches, int ringSetting, int rotation)
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{
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this.type = type;
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this.number = number;
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this.connections = connections;
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this.reversedConnections = reversedConnections;
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this.turnOverNotches = turnOverNotches;
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this.ringSetting = ringSetting;
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this.rotation = rotation;
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}
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/**
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* Factory method that creates a rotor accordingly to the type.
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* Also initialize the rotor with ringSetting and rotation.
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* @param type type indicator (1..10)
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* 1..8 -> I..VIII
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* 9,10 -> Beta, Gamma
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* 11..13 -> DI..DIII
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* @param ringSetting setting of the outer ring (0..25)
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* @param rotation rotation of the rotor
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* @return Concrete rotor
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*/
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public static Rotor createRotor(int type, int rotation, int ringSetting)
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{
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switch (type)
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{
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case 0: return new EntryWheelD();
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case 1: return new RotorI(rotation, ringSetting);
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case 2: return new RotorII(rotation, ringSetting);
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case 3: return new RotorIII(rotation, ringSetting);
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case 4: return new RotorIV(rotation, ringSetting);
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case 5: return new RotorV(rotation, ringSetting);
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case 6: return new RotorVI(rotation, ringSetting);
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case 7: return new RotorVII(rotation, ringSetting);
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case 8: return new RotorVIII(rotation, ringSetting);
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case 9: return new RotorBeta(rotation, ringSetting);
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case 10: return new RotorGamma(rotation, ringSetting);
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case 11: return new RotorDI(rotation, ringSetting);
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case 12: return new RotorDII(rotation, ringSetting);
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case 13: return new RotorDIII(rotation, ringSetting);
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default: return new RotorI(rotation, ringSetting);
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}
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}
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/**
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* Encrypt an input signal via the internal wiring in "forward" direction towards the reflector
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* (using connections)
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* @param input signal
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* @return encrypted signal
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*/
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public int encryptForward(int input)
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{
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return this.connections[normalize(input)];
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}
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/**
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* Encrypt an input signal via the internal wiring in "backwards" direction (using
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* reversedConnections)
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* @param input signal
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* @return encrypted signal
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*/
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public int encryptBackward(int input)
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{
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return this.reversedConnections[normalize(input)];
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}
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/**
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* Return the type indicator (usually 1..5)
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* @return type indicator
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*/
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public String getType()
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{
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return this.type;
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}
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public int getNumber()
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{
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return this.number;
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}
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/**
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* Return the current rotation of the rotor.
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* The rotation consists of the actual rotation - the ringSetting
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* @return rotation-ringSetting
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*/
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public int getRotation()
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{
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return this.rotation;
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}
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/**
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* Increment rotation of the rotor by one.
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*/
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public void rotate()
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{
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this.rotation = normalize(this.getRotation()+1);
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}
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/**
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* Return true, if the rotor is at a position, where it turns over the next rotor by one
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* @return rotation==turnOverNotch
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*/
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public boolean isAtTurnoverPosition()
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{
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for(int x : getTurnOverNotches())
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{
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//if(x == this.rotation + this.ringSetting) return true;
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if(x == this.rotation) return true;
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}
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return false;
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}
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/**
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* Return true, if the rotor is in a position where the double turn anomaly happens.
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* The double turn anomaly (german: Doppelsprung-Anomalie) is an anomaly in the rotor movement
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* caused by the mechanical implementation of the enigma.
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* Whenever the rightmost rotor turns the middle rotor AND the middle rotor is only one move
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* from turning the leftmost rotor, the middle rotor turns again with the next character.
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* So technically there are only 26*25*26 possible rotor settings for any but firmly 3 rotors.
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* @return rotation == turnOverNotch-1
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*/
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public boolean doubleTurnAnomaly()
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{
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for(int x : getTurnOverNotches())
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{
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if(this.rotation == x-1) return true;
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}
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return false;
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}
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/**
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* Returns the positions of the turnover notches in a array
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* @return turnOverNotches
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*/
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public Integer[] getTurnOverNotches()
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{
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return this.turnOverNotches;
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}
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/**
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* Return ringSettings of the rotor
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* @return ringSetting
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*/
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public int getRingSetting()
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{
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return this.ringSetting;
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}
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/**
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* Returns the size (ie the number of wires/size of the connections array)
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* of the rotor
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* @return size
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*/
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public int getRotorSize()
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{
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return this.connections.length;
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}
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/**
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* Normalize the input.
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* Normalizing means keeping the input via modulo in the range from 0 to n-1, where n is equal
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* to the size of the rotor. This is necessary since java allows negative modulo values,
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* which can break this implementation
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* @param input input signal
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* @return "normalized" input signal
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*/
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public int normalize(int input)
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{
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return (input + this.getRotorSize()) % this.getRotorSize();
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}
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/**
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* Concrete implementation of Rotor of type 1 (I)
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* Used in Enigma I, M3, M4
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* E K M F L G D Q V Z N T O W Y H X U S P A I B R C J
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*/
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private static class RotorI extends Rotor
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{
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public RotorI(int rotation, int ringSetting)
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{
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super("I", 1,
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new Integer[]{4, 10, 12, 5, 11, 6, 3, 16, 21, 25, 13, 19, 14, 22, 24, 7, 23, 20, 18, 15, 0, 8, 1, 17, 2, 9},
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new Integer[]{20, 22, 24, 6, 0, 3, 5, 15, 21, 25, 1, 4, 2, 10, 12, 19, 7, 23, 18, 11, 17, 8, 13, 16, 14, 9},
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new Integer[]{17}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 2 (II)
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* Used in Enigma I, M3, M4
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* A J D K S I R U X B L H W T M C Q G Z N P Y F V O E
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*/
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private static class RotorII extends Rotor
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{
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public RotorII(int rotation, int ringSetting)
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{
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super("II", 2,
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new Integer[]{0, 9, 3, 10, 18, 8, 17, 20, 23, 1, 11, 7, 22, 19, 12, 2, 16, 6, 25, 13, 15, 24, 5, 21, 14, 4},
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new Integer[]{0, 9, 15, 2, 25, 22, 17, 11, 5, 1, 3, 10, 14, 19, 24, 20, 16, 6, 4, 13, 7, 23, 12, 8, 21, 18},
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new Integer[]{5}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 3 (III)
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* Used in Enigma I, M3, M4
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* B D F H J L C P R T X V Z N Y E I W G A K M U S Q O
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*/
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private static class RotorIII extends Rotor
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{
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public RotorIII(int rotation, int ringSetting)
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{
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super("III", 3,
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new Integer[]{1, 3, 5, 7, 9, 11, 2, 15, 17, 19, 23, 21, 25, 13, 24, 4, 8, 22, 6, 0, 10, 12, 20, 18, 16, 14},
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new Integer[]{19, 0, 6, 1, 15, 2, 18, 3, 16, 4, 20, 5, 21, 13, 25, 7, 24, 8, 23, 9, 22, 11, 17, 10, 14, 12},
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new Integer[]{22}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 4 (IV)
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* Used in Enigma M3, M4
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* E S O V P Z J A Y Q U I R H X L N F T G K D C M W B
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*/
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private static class RotorIV extends Rotor
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{
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public RotorIV(int rotation, int ringSetting)
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{
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super("IV", 4,
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new Integer[]{4, 18, 14, 21, 15, 25, 9, 0, 24, 16, 20, 8, 17, 7, 23, 11, 13, 5, 19, 6, 10, 3, 2, 12, 22, 1},
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new Integer[]{7, 25, 22, 21, 0, 17, 19, 13, 11, 6, 20, 15, 23, 16, 2, 4, 9, 12, 1, 18, 10, 3, 24, 14, 8, 5},
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new Integer[]{10}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 5 (V)
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* Used in Enigma M3, M4
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* V Z B R G I T Y U P S D N H L X A W M J Q O F E C K
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*/
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private static class RotorV extends Rotor
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{
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public RotorV(int rotation, int ringSetting)
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{
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super("V", 5,
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new Integer[]{21, 25, 1, 17, 6, 8, 19, 24, 20, 15, 18, 3, 13, 7, 11, 23, 0, 22, 12, 9, 16, 14, 5, 4, 2, 10},
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new Integer[]{16, 2, 24, 11, 23, 22, 4, 13, 5, 19, 25, 14, 18, 12, 21, 9, 20, 3, 10, 6, 8, 0, 17, 15, 7, 1},
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new Integer[]{0}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 6 (VI)
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* Used in Enigma M3, M4
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* J P G V O U M F Y Q B E N H Z R D K A S X L I C T W
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*/
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private static class RotorVI extends Rotor
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{
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public RotorVI(int rotation, int ringSetting)
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{
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super("VI", 6,
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new Integer[]{9,15,6,21,14,20,12,5,24,16,1,4,13,7,25,17,3,10,0,18,23,11,8,2,19,22},
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new Integer[]{18,10,23,16,11,7,2,13,22,0,17,21,6,12,4,1,9,15,19,24,5,3,25,20,8,14},
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new Integer[]{0,13}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 7 (VII)
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* Used in Enigma M3, M4
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* N Z J H G R C X M Y S W B O U F A I V L P E K Q D T
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*/
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private static class RotorVII extends Rotor
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{
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public RotorVII(int rotation, int ringSetting)
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{
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super("VII", 7,
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new Integer[]{13,25,9,7,6,17,2,23,12,24,18,22,1,14,20,5,0,8,21,11,15,4,10,16,3,19},
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new Integer[]{16,12,6,24,21,15,4,3,17,2,22,19,8,0,13,20,23,5,10,25,14,18,11,7,9,1},
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new Integer[]{0,13}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type 8 (VIII)
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* Used in Enigma M3, M4
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* F K Q H T L X O C B J S P D Z R A M E W N I U Y G V
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*/
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private static class RotorVIII extends Rotor
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{
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public RotorVIII(int rotation, int ringSetting)
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{
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super("VIII", 8,
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new Integer[]{5,10,16,7,19,11,23,14,2,1,9,18,15,3,25,17,0,12,4,22,13,8,20,24,6,21},
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new Integer[]{16,9,8,13,18,0,24,3,21,10,1,5,17,20,7,12,2,15,11,4,22,25,19,6,23,14},
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new Integer[]{0,13}, ringSetting, rotation);
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}
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}
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/**
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* Concrete implementation of Rotor of type beta (Griechenwalze Beta)
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* Beta was used as a "thin" rotor in the M4. It was thinner than a "normal" rotor, so it
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* could be used together with one of the two thin reflectors as one rotor.
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* When used together with ReflectorThinB, Beta was equivalent to Reflector B (if rotation == 0)
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* That way the M4 was backwards compatible to the M3
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* Used in M4
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*/
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private static class RotorBeta extends Rotor
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{
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public RotorBeta(int rotation, int ringSetting)
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{
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super("Beta", 9,
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new Integer[]{11,4,24,9,21,2,13,8,23,22,15,1,16,12,3,17,19,0,10,25,6,5,20,7,14,18},
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new Integer[]{17,11,5,14,1,21,20,23,7,3,18,0,13,6,24,10,12,15,25,16,22,4,9,8,2,19},
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new Integer[]{}, ringSetting, rotation);
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}
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@Override
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public void rotate()
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{
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//Thin rotors are fixed in position, so they dont rotate
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}
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@Override
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public boolean doubleTurnAnomaly()
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{
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//Nope, no anomaly
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return false;
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}
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}
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/**
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* Concrete implementation of Rotor of type gamma (Griechenwalze Gamma)
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* Gamma was used as a "thin" rotor in the M4. It was thinner than a "normal" rotor, so it
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* could be used together with one of the two thin reflectors as one rotor.
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* When used together with ReflectorThinC, Gamma is equivalent to Reflector C
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* (if rotation == 0). That way the M4 was backwards compatible to the M3
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* Used in M4
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*/
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private static class RotorGamma extends Rotor
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{
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public RotorGamma(int rotation, int ringSetting)
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{
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super("Gamma", 10,
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new Integer[]{5,18,14,10,0,13,20,4,17,7,12,1,19,8,24,2,22,11,16,15,25,23,21,6,9,3},
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new Integer[]{4,11,15,25,7,0,23,9,13,24,3,17,10,5,2,19,18,8,1,12,6,22,16,21,14,20},
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new Integer[]{}, ringSetting, rotation);
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}
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@Override
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public void rotate()
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{
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//Thin rotors are fixed in position, so they don't rotate
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}
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@Override
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public boolean doubleTurnAnomaly()
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{
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//Thin rotors don't do such weird stuff, they're normal just like you and me.
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return false;
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}
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}
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private static class EntryWheelD extends Rotor
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{
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public EntryWheelD()
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{
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super("ETW-D", 0,
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new Integer[]{9,22,20,11,2,12,13,14,7,15,16,25,24,23,8,17,0,3,10,4,6,21,1,19,18,5},
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new Integer[]{16,22,4,17,19,25,20,8,14,0,18,3,5,6,7,9,10,15,24,23,2,21,1,13,12,11},
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new Integer[]{}, 0, 0);
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}
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@Override
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public void rotate()
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{
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//EntryWheel doesn't rotate
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}
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@Override
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public boolean doubleTurnAnomaly()
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{
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//\forall s \in States : nope
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return false;
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}
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}
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/**
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* Rotor I as used in the Enigma Type D
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* L P G S Z M H A E O Q K V X R F Y B U T N I C J D W
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* Turnover Z
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*/
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private static class RotorDI extends Rotor
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{
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public RotorDI(int rotation, int ringSetting)
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{
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super("D-I", 11,
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new Integer[]{11,15,6,18,25,12,7,0,4,14,16,10,21,23,17,5,24,1,20,19,13,8,2,9,3,22},
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new Integer[]{7,17,22,24,8,15,2,6,21,23,11,0,5,20,9,1,10,14,3,19,18,12,25,13,16,4},
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new Integer[]{25}, ringSetting, rotation);
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}
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}
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/**
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* Rotor II as used in the Enigma Type D
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* S L V G B T F X J Q O H E W I R Z Y A M K P C N D U
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* Turnover F
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*/
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private static class RotorDII extends Rotor
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{
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public RotorDII(int rotation, int ringSetting)
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{
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super("D-II", 12,
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new Integer[]{18,11,21,6,1,19,5,23,9,16,14,7,4,22,8,17,25,24,0,12,10,15,2,13,3,20},
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new Integer[]{18,4,22,24,12,6,3,11,14,8,20,1,19,23,10,21,9,15,0,5,25,2,13,7,17,16},
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new Integer[]{5}, ringSetting, rotation);
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}
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}
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/**
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* Rotor III as used in the Enigma Type D
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* C J G D P S H K T U R A W Z X F M Y N Q O B V L I E
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* Turnover O
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*/
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private static class RotorDIII extends Rotor
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{
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public RotorDIII(int rotation, int ringSetting)
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{
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super("D-III", 13,
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new Integer[]{2,9,6,3,15,18,7,10,19,20,17,0,22,25,23,5,12,24,13,16,14,1,21,11,8,4},
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new Integer[]{11,21,0,3,25,15,2,6,24,1,7,23,16,18,20,4,19,10,5,8,9,22,12,14,17,13},
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new Integer[]{14}, ringSetting, rotation);
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}
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}
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}
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