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Dna Cryptography

Nov 26, 2014




AN ENCRYPTION SCHEME USING DNA TECHNOLOGY ByDept. of Control of Science & Engineering, Houzang Uni. China Delivered By


SCHEME OF PRESENTATION Introduction to DNA Structure of DNA Why DNA Computing ? Polymerase Chain Reaction(PCR) DNA Digital Coding Encryption Scheme Conclusion

INTRODUCTION TO DNA DNA (Deoxyribonucleic acid) DNA represents the genetic blueprint of living creatures DNA is organized into chromosomes , which are present within the nuclei of the cells. A gene is a segment of DNA on a chromosome that codes for a specific protein and thus determines a trait.

STRUCTURE OF THE DNA DNA is made of 2 long strands of nucleotides arranged in a specific way called the "Complementry Rule Sides Sugar-phosphate backbones ladders complementary base pairs Adenine & Thymine Guanine & Cytosine

STRUCTURE OF DNA Two strands are held together by weak hydrogen bonds between the complementary base pairs

GENETIC DIVERSITY Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.

WHY DNA COMPUTING ? Limitations of Moor s law Life cycle of silicon chip will come to an end. Intel scientists say it will happen in about the year 2018 Require a successor to silicon.

WHY DNA COMPUTING ? It provides massive parallel processing. Huge storage capability. A super computer can achieve 10^12 ops /sec. In sharp contrast the DNA computers can achieve speeds up to 10^17 ops/ sec.

POLYMERASE CHAIN REACTION (PCR) The polymerase chain reaction (PCR) is scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies a particular DNA sequence.


DNA DIGITAL CODING binary digital coding has a base of 2, and anything can be encoded by two state 0 or 1 DNA Digital Coding has four kinds of bases, which are adenine (A) and thymine (T) or cytosine (C) and guanine (G) in DNA sequence. The simplest coding patterns to encode the 4 nucleotide bases (A, T, C, G) is by means of 4 digits: 0(00),1(01), 2(10), 3(11).

DNA DIGITAL CODING DNA digital coding follows a WatsonCrick complementary rule i.e. (~0)=1, and (~1=0) . According to this complementary rule, DNA digital code 0(00) complements to 3(11) and 1(01) complements to 2(10).

ENCRYPTION SCHEME Key Generation The message-sender Alice designs a forward primer for PCR amplification & sends it to bob Bob also designs a reverse primer for PCR amplification and transmits it to Alice over a secure channel.

ENCRYPTION SCHEME The exchange of pair of PCR primers gives: Encryption key KA that is a pair of PCR primers Bob s public key e, decryption key KB that is a pair of PCR primers Bob s secret key d.

ENCRYPTION PRETREATMENT DATA PROCESS Convert plain text to hexadecimal Convert hexadecimal into binary plain text M . M is converted into the binary cipher text C by using Bob s public key e. Binary cipher text C is converted into DNA sequence according to the DNA digital coding technology. secrete-message DNA sequence is placed among dummies.

DECRYPTION Bob picks up the secret-message DNA sequence by using the correct primer pairs. Bob translates the secret-message DNA sequence into the binary ciphertext C . C is decrypted into M by using secret key e. Applying data post treatment on M gives M.


CONCLUSION Technologies used in this scheme: DNA synthesis. PCR amplification DNA digital coding . Traditional cryptography. Security Concerns PCR two primer pairs used as key Complex biological operations Cryptographic algorithms