Team:Davidson-Missouri Western/Project

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E. nigma Project Overview: Using E. coli to compute values of a cryptographic hash function

A recent article about cryptographic hash functions challenged the world to create a better hash function, an algorithm that produces a digital fingerprint of a digitized message. We decided to work toward the design and construction of a bacterial hash function. To this end, we designed and constructed several novel dually-regulated hybrid promoters, crucial new elements in the genetic circuitry we designed to function as biological XOR gates. These gates produce a positive result in the presence of exactly one input and a negative result otherwise and can be put in sequence to create a bacterial hash function. The name of the project is a play on the name of the World War II coding machine used to encrypt military secrets.

Our multidisciplinary team conducted a project that drew expertise from biology and mathematics to explore the possibility of designing, modeling, constructing, and testing logic gates that would enable bacteria to compute a hash function. The links below provide documentation of the diverse outcomes of our research, illustrating not only the feasibility of bacterial computation but the ability of undergraduates students to contribute to an important emerging field.

Cryptographic Hash Functions

A cryptographic hash function takes as input a message or document of any size, and returns a fixed length hexadecimal string as output, called the hash value. The current widely-held standard is called MD-5. The hash value is essentially the "digital signature" of the input document, and can be used in many cases to determine if a document has been tampered with. The hash function should be sensitive to small perturbations in the input message, producing very different hash values for highly similar, but not identical, documents. To learn more about the properties of hash function and our biological implementation of hash functions, use the links below.

Properties of Good Hash Functions

Applications of Hash Functions

• Prove authentication of document

• Protect Government Documents

• Minimize Cheating on Standardized Tests

• Protect Lengthy and Important Instructions

• Protect Financial Transactions

• Protect Passwords

• Detect tampered pictures (pictures that have been photo-shopped) Detect tampered pictures with hidden info (terrorists)

Hash functions and biological systems

Our Models

Analysis of our Models

Matlab files

Future work

Define XOR logic gates and how it was used with biological inputs and outputs

XOR and Autoinducers

Describe different design architectures

DNA Encoded XOR Gates

Describe cellular communication systems used

Cellular Communication Systems

parts contributed

Constructs tested

Systems for sending and receiving

Discuss need for delayed growth (common problem with many projects in the past)

Time-Delayed Growth (See the QT Movie)

Present Hybrid Promoter Designs cartoon fashion (3 major different types)

Hybrid Promoters

Show data we have with new parts

Experimental data on XOR gate

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