DNA Computers Applications: Cryptography

1
DNA Computers ApplicationsCryptography

• Constanza Lampasona
• Innovative Computer Architectures and Concepts
• Computer Architecture Department - University of
  Stuttgart

2
Motivation

• Silicon technologies have limits
• Research intends to deal with silicon
  disadvantages
• DNA computing -gt inherent parallelism
• Cryptographic problem requires vast parallelism

Lets solve the cryptographic problem using a
molecular computer!!!
3
Outline

• 1. Introduction
• 2. Cryptography
• 3. DNA Computing
• 4. Breaking DES using a molecular computer
• 5. Conclusions

4
Introduction

• Encoding data as in nature

5
Introduction

• Cryptography

Secret writing
Gjoejoh uif lfz
Data Encryptation Standard approved
cryptographic algorithm as required by FIPS
140-1 (Federal Information Processing Standards)
6
Outline

• 1. Introduction
• 2. Cryptography
• 3. DNA Computing
• 4. Breaking DES using a molecular computer
• 5. Conclusions

7
Cryptography
Lets look at history...
8
Cryptography

• Encryption

9
Cryptography

• Decryption

10
Cryptography
Decryption
Encryption
Secret KEY
11
Cryptography
Encrypted data (cipher-text) Khoor zruog
Secret KEY shift by 3
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
Decrypted data (plain-text) Hello world
12
Cryptography

• Data Encryption Standard (DES)

• Crytographic algorithm (National Bureau of
  Standards).
• Enciphering and Deciphering.
• 64-bit key.
• Data depends on keys security.
• Unique key for encryting and decryting.

13
Cryptography

• DES Data Encryption Algorithm
• Enciphering

14
Cryptography
Initial permutation IP
Inverse initial permutation IP -1
Computation
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 1 59 51 43 35 27 19
11 3 61 53 45 37 29 21 13
5 63 55 47 39 31 23 15 7
15
Cryptography
Initial permutation IP
Inverse initial permutation IP -1
Computation
Input
Output

• Uses the permuted input block as input.
• Produces a pre-output block.
• 16 iterations.

16
Cryptography
Initial permutation IP
Inverse initial permutation IP -1
Computation
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 28 35 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
17
Outline

• 1. Introduction
• 2. Cryptography
• 3. DNA Computing
• 4. Breaking DES using a molecular computer
• 5. Conclusions

18
DNA Computing

• DNA

19
DNA Computing

• The Structure of DNA

20
DNA Computing
DNA Computer DNA Strands Combinations
Solution

• Based on Adlemans work (1994)
• Solve huge problems by parallel search
• Much faster than a conventional computer
• More hardware vs. more DNA

21
Outline

• 1. Introduction
• 2. Cryptography
• 3. DNA Computing
• 4. Breaking DES using a molecular computer
• 5. Conclusions

22
Breaking DES

• The Idea

• Finding a key given one pair (plain-text,
  cipher-text).
• Pre-processing one day of work recover the
  key.
• First example of a real problem solved using DNA.

23
Breaking DES

• Massive parallel DNA computing approach

• Generate all possible solutions in parallel
• Remove wrong solutions

24
Breaking DES

• Representing binary strings
• Plan of DES attack
• Prepare the DNA solution
• Extract desired patterns
• Read the result
• Break DES!!!

25
Breaking DES

• Summary of the experiment

• 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

DNA Computer DNA Strands Combinations
Solution
26
Outline

• 1. Introduction
• 2. Cryptography
• 3. DNA Computing
• 4. Breaking DES using a molecular computer
• 5. Conclusions

27
Conclusions

• 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

28
Summary

• Cryptography
• DES
• DNA Computing gtgtgt Parallelism
• Breaking DES

29
http//www.ra.informatik.uni-stuttgart.de/virazel
a/Seminar/Material/Presentation8/