Presentation DNA Cryptography

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DNA Computers Applications:DNA Computers Applications:

CryptographyCryptography

Constanza Lampasona

Innovative Computer Architectures and Concepts

Computer Architecture Department - University of Stuttgart



June 2002 DNA Computers Applications: Cryptography 2

MotivationMotivation

SiliconSilicon technologies have limitslimits

Research intends to deal with ³silicon´ disadvantagesdeal with ³silicon´ disadvantages

DNA computingDNA computing -> inherent parallelisminherent parallelism

Cryptographic problemCryptographic problem requires vast parallelism

Let¶s solve the cryptographic problem using a molecular computer!!!Let¶s solve the cryptographic problem using a molecular computer!!!




OutlineOutline1. Introduction

2. Cryptography

3. DNA Computing

4. Breaking DES using a molecular computer

5. Conclusions




IntroductionIntroduction Encoding data ³as in nature´

Recombination

algorithmInput Output




IntroductionIntroduction Cryptography

Gjoe joh uif lfz Shift by oneShift by one Finding the key

Secret writing

Data Encryptation Standard: approved c ryptographi c algorithmc ryptographi c algorithm as

required by FIPS 140-1 (Federal Information Processing Standards)





2. Cryptography

3. DNA Computing


5. Conclusions





³The art of writing wit h a secret key secret key or in an enigmatic way´

From the Greek: cryptocrypto--,, hidden + --graphy graphy , writing

Let¶s look at history...




CryptographyCryptography Encryption

Protecting information

Ensure privacyprivacy

Keep the information hiddeninformation hidden

Data Transformation Unreadable form




CryptographyCryptography Decryption

Reverse of Encryption

Encrypted data Transformation Intelligible form





Encryption Decryption

Secret KEY




CryptographyCryptographyEncrypted data (cipher-text): Khoor zruog

Secret KEY: shift by 3

Decrypted data (plain-text): Hello world

a b c d e f g h i j k l m n o p q r s t u v w x y z

d e f g h i j k l m n o p q r s t u v w x y z a b c




CryptographyCryptography Data Encryption Standard (DES)

Crytographic algorithm (National Bureau of Standards).

E nciphering E nciphering and Deciphering Deciphering.

64-bit key.

Data depends on key¶s security.

Unique keyUnique key for encryting and decryting.




CryptographyCryptography DES¶ Data Encryption Algorithm

E nc iphering

Initial

permutation

IP

ComputationInverse initial

permutation

IP -1

Input Output




CryptographyCryptographyInitial

permutation

IP


permutation

IP -1

Input Output

IP

58 50 42 34 26 18 10 2

60 52 44 36 28 20 12 4

62 54 46 38 30 22 14 6

64 56 48 40 32 24 16 8

57 49 41 33 25 17 9 159 51 43 35 27 19 11 3

61 53 45 37 29 21 13 5

63 55 47 39 31 23 15 7





permutation

IP


permutation

IP -1

Input Output

Uses the permuted input block as input.

Produces a pre-output block.

16 iterations.





permutation

IP


permutation

IP -1

Input Output

IP-1

40 8 48 16 56 24 64 32

39 7 47 15 55 23 63 31

38 6 46 14 54 22 62 30

37 5 45 13 53 21 61 29

36 4 44 12 52 20 60 2835 3 43 11 51 19 59 27

34 2 42 10 50 18 58 26

33 1 41 9 49 17 57 25

Plain-text Cipher-text

Key





2. Cryptography

3. DNA Computing


5. Conclusions




DNA ComputingDNA Computing

DNADNA(Deoxyribonucleic acid) GeneticGenetic information ³memory´

NucleotidesNucleotides strung into

polymer chainspolymer chains (DNA Strands)

Four classes of nucleotides:

Adenine, Guanine, Cytosine, Thymine Adenine, Guanine, Cytosine, Thymine (A,C,G,T)

DNA




DNA ComputingDNA Computing The Structure of DNA

The double helix structure discovered by Watson and Crick




DNA ComputingDNA Computing

Based on Adleman¶sAdleman¶s work (1994)

Solve huge problemshuge problems by parallel search

Much faster Much faster than a conventional computer

More hardwareMore hardware vs. more DNA

DNADNA

Computer:Computer:

DNA Strands

+

Combinations

=

³Solution´

DNADNA

Computer:Computer:

DNA Strands

+

Combinations

=

³Solution´





2. Cryptography

3. DNA Computing


5. Conclusions




Breaking DESBreaking DES

FindingFinding aa keykey given one pair one pair (plain-text, cipher-text).

PrePre--processingprocessing + one day of workone day of work = recover the key.

First exampleFirst example of a real problem solved using DNA.

The Idea





Generate all possible solutions in parallelGenerate all possible solutions in parallel

Remove wrong solutionsRemove wrong solutions

Massive parallel DNA computing approach:





Representing binary stringsRepresenting binary strings

Plan of DES attackPlan of DES attack

Prepare the DNA solutionPrepare the DNA solution

Extract desired patternsExtract desired patterns

Read the resultRead the result

Break DES!!!Break DES!!!





DES(M0,k) encoding plain-text with all possible 256 keys

4 months

Extract DES(M0,k)=E0, (plaintext, cipher-text)

Read k

1 day

Summary of the experiment

DNA Computer:DNA Computer:

DNA Strands+

Combinations

=

³Solution´

DNA Computer:DNA Computer:

DNA Strands+

Combinations

=

³Solution´





2. Cryptography

3. DNA Computing


5. Conclusions




ConclusionsConclusions DNA computing with a concrete application,

Cryptography

Very general attack on DES, using 64-bit key

Cryptosystems with 64-bit key are insecure

Future of molecular computers: Unclear




SummarySummary

Cryptography

DES

DNA Computing >>> Parallelism

Breaking DES



Documents

Presentation DNA Cryptography