# Project Abstract

E. nigma: XOR Gates, a Bacterial Hash Function, and Viz-A-Brick

The team designed, modeled, and constructed a bacterial computer that uses XOR logic to compute a cryptographic hash function. Hash functions are used to authenticate the integrity of a document by computing its digital "fingerprint," an integer value that can be compared to the publicized value. Our bacterial computers recognize the presence or absence of two chemical signals, converting biological information into binary numbers. Given a starting "key" and a binary message of arbitrary length, various configurations of the designed system produce the hash function output. Mathematical modeling of these computers has shown that our hash functions are difficult to corrupt. We also produced a graphical interface for exploring the Registry of Standard Biological Parts called Viz-A-Brick (http://gcat.davidson.edu/VizABrick/ <http://gcat.davidson.edu/VizABrick/> ), and other web-based tools to improve the construction of new parts with BioBrick ends http://gcat.davidson.edu/iGEM08/tools.html) <http://gcat.davidson.edu/iGEM08/tools.html)> .