NON-REVEALING CRYPTOSYSTEM
by
Kanokwan Wongwatanasin

Examination Committee :

Prof. Dr. Srisakdi Charmonmam

Air Marshal Dr. Chulit Meesajjee

Dr.Prapon Phasukyud

Dr.Vichit Avatchanakorm

Dr.Pornchai Phutlek

Dr.Suphamit Chittayasothorn

Dr.Aran Namphol

Assoc. Prof.Somchai Thayanyong

Name:

Kanokwan Wongwatanasin

Nationality :

Thai

Previous Degree :

Bachelor of Business Administration

Chulalongkorn University Bangkok, Thailand

Master of Business Administration

Boston University,USA

Approval Page

RESEARCH TITLE	:	NON-REVEALING CRYPTOSYSTEM
CANDIDATE NAME	:	Kanokwan  Wongwatanasin
ADVISOR NAME	:	Prof.Dr.Srisakdi Charmonman
ACADEMIC YEAR	:	1996

The Graduate School of Assumption University had approved this dissertation as a partial fulfillment of the requirement for the degree of Doctor of Philosophy in Computer and Engineering Management

Abstract

With the Internet gaining more popularity, both business and private citizens have become more concerned with computer and network security. A very good method to provide computer and network security is encryption.Most of the cryptosystems are revealing in the sense that thay give ciphertext which distinctively reveals the fact that it has been encrypted and, thus, invite attention from the potential attackers. Therefore, it is highly desirable to produce new cryptosystems which are non-revealing,i.e. whose ciphertext dose not reveal itself as having been encrypted.

In this dissertation,the author proposed 29 encryption algorithms, all of which are not obviously revealing in the sense that the cipheretext dose not look like having been encrypted. It looks like a list, a table, or an English sentence or passage. The 29 encryption algorithms are named KSC1 to KSC29 for ease of identification and to honor the KSC group of companies which allowed the author to work on her dissertation while working for the companies.

In KSC1 to KSC12,the ciphertext is in the form of a list of things. KSC1to KSC5 give the ciphertext as a list of personal names; KSC6 a list of countries; KSC7 a list of cities; KSC8 a list of flowers; KSC9 a list of household objects; KSC10 a list of transfers of persons to countries; KSC11 a list of transfers of persons to cities; and KSC12 a price list.

In KSC13 to KSC22, the ciphertext isin the form of a table. KSC13 gives a table of names and ages; KSC14 a table of names and identification numbers; KSC15 a table of EXIM products and values; KSC16 a requisition order table; KSC17 a purchase-order table; KSC18 a able of names and years; KSC19 a table of names, years, months and days; KSC20 a table of names and percentages; KSC21 a table of names and account number; and KSC22 a table of account numbers, names and balances.

In KSC23 to KSC28,the ciphertext is in the form of English sentences or passages or paragraphs. KSC23 gives three-word sentences; KSC24 four-word sentences; KSC25 n-word sentences; KSC26 a garden story;KSC 27 a shopping story; and KSC28 a wardrobe story. While KSC1 to KSC28 were for encrypting of text, KSC29 was proposed for encrypting numbers such as telaphone numbers.

Two sample applications of the proposed encryption algorithms were made for traffic control messages and email massages. The algorithms were also coded in Visual Basic to show that they can be easily computerized. In conclusion, the proprosed 29 cryptosystems are non-revealing in the sense that none of them obviously reveal its ciphertext as having been encrypted. The proposed concept could also be utilized to produce many more similar algorithms.

Acknowledgment

The author would like to express her sincere appreciation to her major advisor, Professor Dr.Srisakdi Charmonman,and the administrative advisor, Dr.Prapon Phasukyud, for their providing the author with inspiration, advice, guidance and encouragement throughout the course of the research. She is highly grateful to the Dissertation Committee and the Final Examination Committee whose chairman, Professor Dr.Srisakdi Charmonman, and all the members,namely, Associate Professor Somchai Thayanyong, Air Marshal Dr.Chulit Meesajjee, Dr.Vichit Avatchanakorn, Dr. Prapon Phasukyud, Dr.Pornchai Phutlek, and Dr.Suphamit Chittayasothorn, have kindly provided her with suggestions and comments to improve the dissertation. She is also indebted to the top executives of the KSC Group of companies and the Internet Knowledge Service Center of Assumption University for allowing her to work on the Ph.D. dissertation while working for the group and the center.

Rev. Bro. Dr. Prathip Martin Komolmas, the President of Assumption University, deserves very special thanks for his leadership in providing all the neccessary resources to make the Ph.D. program a success.

The supporting staff members of the KSC Group of companies and the Internet Knowledge Service Center must be given special mantion,especially,Wuth Wongwaiwit and Krit Viriyatharangkurn for coding and testing the sample program to demonstrate the algorithms she developed; Suda Supaksoradej, Porntipa Chanit, Siriporn Sornsudhi, Dork-or Phutsom and Donnapa Chantra for typewriting; and Myo Kyaw Myint for proofreading. All members of her group of close friends should also be thanked for their understanding that she did not have time to go shopping with them during the few years she was a Ph.D.student.

Last but not the least, very special mention must be given to her parents without whose support and understanding she would not have been able to complete all the requirements for the Ph.D.degree.

Table of Contents

List of Figures

List of Tables

Chapter I INTRODUCTION

1.1 Introduction

1.2 Threats in Computer Security

1.3 Types of Security and Encryption

1.4 Cryptosystem

1.5 Substitution Cipher

1.6 Transposition Cipher

1.7 Statement of Purposes

1.8 Research Objectives

1.9 Scope of Study

1.10 Methodology

1.11 Definition of Terms and Nomenclature

1.12 Layout of the Dissertation

Chapter II LITERATURE REVIEW

2.1 The Importance of Computer Security

2.2 Computer Privacy

2.3 Encryption

2.4 Internet Security

2.5 Internet

2.6 Doctoral Dissertations

Chapter III PROPOSED KSC CRYPTOSYSTEMS

3.1 Revealing Cryptosystem

3.2 The New Non-Revealing Cryptosystems

3.3 KSC Group of Ciphers

3.4 KSC1-5 Ciphers

3.5 KSC6-9 Ciphers

3.6 KSC10-11Ciphers

3.7 KSC12 Price-List Ciphertext

Chapter IV CIPHERTEXT IN TABULAR FORM

4.1 KSC13 Name and Age Ciphertext

4.2 KSC14 Name and ID Ciphertext

4.3 KSC15 EXIM Product and Value Ciphertext

4.4 KSC16 Requisition-Order Ciphertext

4.5 KSC17 Purchase-Order Ciphertext

4.6 KSC18 Name and Four-Digit Year Ciphertext

4.7 KSC19 Name and Six-Digit Date Ciphertext

4.8 KSC20 Name and Percentage Ciphertext

4.9 KSC21 Name and Account Number Ciphertext

4.10 KSC 22 Account No.,Names and Balance Ciphertext

Chapter V ENGLISH SENTENCE AND STORY CIPHERTEXT

5.1 KSC23 Three-Word Sentential Ciphertext

5.2 KSC24 Four-Word Sentential Ciphertext

5.3 KSC25 N- Word Sentential Ciphertext

5.4 KSC26 Garden-Story Ciphertext

5.5 KSC27 Shopping-Story Ciphertext

5.6 KSC28 Wardrobe-Story Ciphertext

5.7 KSC29 An Application to Traffic Control

5.8 KSC30 Internet-to-Pager Email Massages

5.9 A Computerized Test

Chapter VI CONCLUSIONS AND RECOMMENDATIONS

6.1 Conclusions

6.2 Recommendation for Further Studies

REFERENCES

APPENDICES

A Personal Name

B Keys

C List of Countries

D List of Cities

E List of Flowes

F List of Household Objects

G Price List

H EXIM Products and Values

I Single-Word Verbs

J Two-Word Verbs

K Two-Word Verbs and Adverbs

L List of Things in the Closet

M About the Ph.D.Candidate