Enigma Machine - Design Presentation Group M1 Adithya Attawar Shilpi Chakrabarti Zavo Gabriel Michael Sokolsky Digital World War II Enigma Cipher Wed. Jan 25 Initial Design

Status  Finished:  Design selections  Block diagram for processes  To Do:  Verilog  Schematic  Layout  Testing  Simulation

Design Decisions  Project Overview  Implement on chip the functionality of a World War II Enigma cipher machine.  A sophisticated variation on a simple substitution code, it involves a string of 9 letter pair substitutions, some of which change for each new character sent through it.  Must re-create the effect of both the electrical and mechanical aspects of the device on chip.  User must be able to change the configuration.  We will represent each character as a 5-bit number.

Design Decisions cont.  Project Overview  Initial settings are:  8 Possible wheels (4 bits)  3 Wheels (15 bits)  Plugboard (12 bits)  Signal travels through plugboard, 3 wheels, reflector, back through 3 wheels, back through plugboard, illuminates encoded letter.  Historically significant code, breaking it had a significant impact on WWII

Block Overview

Block Functions  Logic Array trans.  Emulates pegboard to swap characters, fundamentally a programmable FSM  Direction Select trans.  Routes the character through 3 of the 8 wheels in the correct order, then through the Reflector, back through the wheels, and then back to the Logic Array  Wheel Logic trans.  Takes input character and wheel position and outputs a swapped character  Reflector/Registers trans.  Performs a fixed character swap and holds the result for the next cycle, to pass back through all of the previous logic

Questions? Adding more encryption options? The ability to have A->A Automatic key generation? Randomized wheel movement?