Free Essay

Performance Analysis of Substitution Cipher Based Cryptographic Algorithm

In: Computers and Technology

Submitted By mihir2891
Words 2433
Pages 10
Performance analysis of Substitution Cipher Based Cryptographic Algorithm Mihir Sanghavi
11MCA48, Student, MCA Programme, Institute of Technology, Nirma University, Ahmadabad

Email: 11MCA48@nirmauni.ac.in

Abstract
Cryptography is the study of Encryption techniques related to aspects of information security, such as confidentially or privacy, data integrity and entity authentication. Today’s world, for secure data transmission via Internet or any public network, there is no alternative to cryptography. The role of Cryptography is most important in the field of network security. The main goal of cryptography is Confidentiality, Integrity, Authentication, Non repudiation. Cryptography is widely used by governmental and intelligence agencies around the world to safe transmission of any format of messages online or offline. In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with cipher text, according to a regular system; the "units" may be single letters, pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing an inverse substitution. Caesar cipher is an example of substitution cipher method. In this paper substitution cipher based cryptography algorithms are compared and performance is evaluated.

Keywords
Cryptography, substitution cipher, cryptanalysis, Caesar cipher, monoalphabetic cipher and Polyalphabetic cipher.

Introduction
A substitution cipher is a method of encryption by which units of plaintext are replaced with cipher text, according to a regular system; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing an inverse substitution. Substitution ciphers can be compared with transposition ciphers. In a transposition cipher, the units of the plaintext are rearranged in a different and usually quite complex order, but the units themselves are left unchanged. By contrast, in a substitution cipher, the units of the plaintext are retained in the same sequence in the cipher text, but the units themselves are altered.

There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters is termed polygraphic. A monoalphabetic cipher uses fixed substitution over the entire message, whereas a Polyalphabetic cipher uses a number of substitutions at different positions in the message, where a unit from the plaintext is mapped to one of several possibilities in the cipher text and vice versa.

Key findings from literature survey: Monoalphabetic Cipher
If the substitution cipher operates on single letters, it is termed as monoalphabetic cipher. There are various types of monoalphabetic cipher i.e. Caesar cipher, pigpen cipher, ADFGVX cipher. In monoalphabetic cipher shifting is done by value K. If we think in terms of the numbers 0 through 25 representing the letters A through Z, the enciphering process may be viewed mathematically as C = M + K (mod 26), where C is the cipher text letter, M is the plaintext letter, and K is the key. The “mod 26” part (short for “modulo 26”) simply means that if the sum M + K is greater than or equal to 26, we subtract 26 from this number to get our result. The key space (defined as the set of possible choices for K) has 25 elements, since the identity K = 0 leaves the message unchanged, as does K = 26. Only values strictly between 0 and 26 offer distinct decipherments. A longer key phrase may be used to determine the order of the substitutions. If a letter is repeated, simply ignore it when it reappears, 7 as you write the cipher alphabet out. Key phrases may be chosen that contain all of the letters of the alphabet. i.e. 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 plaintext THEQUICKBROWNFXJMPSVALZYDG Richard Lederer provides several shorter phrases using all 26 letters:  Pack my box with five dozen liquor jugs (32 letters)  Jackdaws love my big sphinx of quartz. (31 letters)  How quickly daft jumping zebras vex. (30 letters)  Quick wafting zephyrs vex bold Jim. (29 letters)  Waltz, nymph, for quick jigs vex Bud. (28 letters)  Bawds jog, flick quartz, vex nymphs. (27 letters)  Mr. Jock, TV quiz Ph.D., bags few lynx. (26 letters – a minimum) A few devices have been invented to ease translation from plaintext to cipher text and back again.

The manner in which this disk can be used to encrypt and decrypt should be immediately clear and require no explanation. The inner alphabet is on a separate disk that may be rotated with respect to the larger disk in order to form other substitutions.

Caesar Cipher
The earliest known use of a substitution cipher, and the simplest, was by Julius Caesar. The Caesar cipher involves replacing each letter of the alphabet with the letter standing three places further down the alphabet. The Caesar cipher is named after Julius Caesar, who, according to Suetonius, used it with a shift of three to protect messages of military significance. While Caesar's was the first recorded use of this scheme, other substitution ciphers are known to have been used earlier. For example: Plain: meet me after the toga party Cipher: PHHW PH DIWHU WKH WRJD SDUWB

We can define the transformation by listing all possibilities, as follow:

Plain: 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 Cipher: 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 Let us assign a numeric equivalent to each letter: Then the algorithm can be expressed as follows. For each plaintext letter p, substitute the cipher letter C: C = E (p) = (P+3) mod (26) A shift may be of any amount, so that the general Caesar algorithm is

C = E (p) = (p+k) mod (26) Where, k takes on a value in the range 1 to 25. The decryption algorithm is simply P = D(C) = (C-k) mod (26)

Cryptanalysis
    Only have 25 possible ciphers. A maps to B up to Z. Given cipher text, just try all shifts of letters. Do need to recognize when we have plain text.

Pigpen cipher
It is variation on letter substitution; here alphabets are arranged as follows:

X Y Z

W

W=

X=

Y=

Z=

Alphabets will be represented by this symbols but it is a weak cipher.

ADFGVX cipher:
This is a variation on substitution cipher and is a strong cipher.

A A D F G V X 8 L 7 J X 9

D P T K U S E

F 3 4 B 6 V Y

G D O C W I 0

V 1 A 5 G R F

X N H Z M 2 Q

Remove spaces and punctuation marks from message For each letter or number substitute the letter pair from the column and row heading Next, use a transposition operation on the pair of letters using a key word (which the receiver knows) Rearrange the columns of the new arrangement in alphabetical order Finally, arrange the letters from consecutive columns E.g., Message = SEE ME IN MALL VD XD XD GX XD VG AX GX DV DA DA Keyword: INFOSEC ARRANGE LEVEL 1 CIPHER IN A GRID. AND THEN ARRANGE IT IN ALPHABETICAL ORDER. FRESH GRID:

I V X G

N D X X

F X D D

O D V V

S X G D

E D A A

C G X V

ORDERED GRID: C G X V E D A A F X D D I V X G N D X X O D V V S X G D

Cipher text is: GXVDAAXDDVXGDXXDVVXGD Recipient reverses the process using the same keyword and gets the plaintext Reason for this cipher using the name ADFGVX is that in Morse code these characters all have dissimilar patterns of dots and dashes.

Cryptanalysis:
The ADFGVX cipher is not hard to spot, but this is a very difficult cipher to break. Let us consider the problems that are faced when crypt analyzing the ADFGVX ciphers. First, consider a message that was encrypted once with a Caesar cipher and then again with columnar transposition. Frequency analysis will show a shifted alphabet, but, after shifting the cipher text letters back by the key that was determined from frequency analysis, the message will still not be plain text. Frequency analysis would indicate plaintext, but the message would not be plaintext. That indicates a transposition cipher, and the remaining cipher text would be attacked as a transposition cipher. Similarly, consider a message that was encrypted once with a simple substitution cipher with a randomly generated permutation and then again with a columnar transposition. Frequency analysis will show a simple substitution cipher. The cryptanalyst might begin by assuming that the most frequent cipher text letter corresponds to plaintext e, etc., but the transposition would complicate this analysis. The ADFGVX cipher is even worse The ADFGVX cipher is even worse. If only the substitution portion of the cipher were done, it would not be difficult to break. Even if the cryptanalyst knew nothing about the ADFGVX cipher, the fact that only six letters appear in the cipher text and every cipher text message has even length would suggest that a checkerboard was used for substitution. Suspecting this, the message could be broken into

digraphs and the frequency of the digraphs could be analyzed to determine the corresponding plaintext letters as is done for any simple substitution cipher. The devil is the transposition. Every plaintext letter is substituted by a digraph. When placed into the rectangular array for columnar transposition, the first letter of the digraph will lie in one column and the second letter of the digraph will lie in another column. After transposition, these letters will be separated – the plaintext frequencies will be “fractionated.” This is the strength of the ADFGVX cipher and similar ciphers. Single-letter characteristics are scattered.

Polyalphabetic Cipher: • • • • In monoalphabetic cipher the problem was that each character was substituted by a single character. Cryptanalysts are helped by the fact that they have to see what character would correspond in plaintext for a given cipher text character Polyalphabetic cipher’s goal is to make this process difficult

In Polyalphabetic cipher, each plaintext character may be replaced by more than one character • Since there are only 26 alphabets this process will require using a different representation than the alphabets • Alphabets ‘A’ through ‘Z’ are replaced by 00, 01, 02, .., 25 • We need two digits in this representation since we need to know how to reverse the process at the decryption side The most common methods used are Vigenère cipher, Beale cipher, Vernam cipher.

Vigenère cipher
• • • Vigenère cipher starts with a 26 x 26 matrix of alphabets in sequence. First row starts with ‘A’, second row starts with ‘B’, etc. Like the ADFGVX cipher, this cipher also requires a keyword that the sender and receiver know ahead of time Each character of the message is combined with the characters of the keyword to find the cipher text character

ABCDEFGHIJKLMNOPQRSTUVWXYZ AABCDEFGHIJKLMNOPQRSTUVWXYZ B B A B C D E F G H I J K L M N O P Q R S T U V W X YA CCDEFGHIJKLMNOPQRSTUVWXYZAB DDEFGHIJKLMNOPQRSTUVWXYZABC EEFGHIJKLMNOPQRSTUVWXYZABCD FFGHIJKLMNOPQRSTUVWXYZABCDE GGHIJKLMNOPQRSTUVWXYZABCDEF HHIJKLMNOPQRSTUVWXYZABCDEFG IIJKLMNOPQRSTUVWXYZABCDEFGH JJKLMNOPQRSTUVWXYZABCDEFGHI KKLMNOPQRSTUVWXYZABCDEFGHIJ LLMNOPQRSTUVWXYZABCDEFGHIJK MMNOPQRSTUVWXYZABCDEFGHIJKL NNOPQRSTUVWXYZABCDEFGIJKLM OOPQRSTUVWXYZABCDEFGIJKLMN PPQRSTUVWXYZABCDEFGIJKLMNO QQRSTUVWXYZABCDEFGIJKLMNOP RRSTUVWXYZABCDEFGIJKLMNOPQ SSTUVWXYZABCDEFGIJKLMNOPQR TTUVWXYZABCDEFGIJKLMNOPQRS UUVWXYZABCDEFGIJKLMNOPQRST VVWXYZABCDEFGIJKLMNOPQRSTU WWXYZABCDEFGIJKLMNOPQRSTUV XXYZABCDEFGIJKLMNOPQRSTUVW YYZABCDEFGIJKLMNOPQRSTUVWX ZZABCDEFGIJKLMNOPQRSTUVWXY

For example: Message = SEE ME IN MALL Take keyword as INFOSEC Vigenère cipher works as follows:

SEEMEI NMALL INF OSEC I NFO -------------------------------ARJAWMPUNQZ To decrypt, the receiver places the keyword characters below each cipher text character. Using the table, choose the row corresponding to the keyword character and look for the cipher text character in that row, plaintext character is then at the top of that column. Decryption of cipher text:

ARJAWMPUNQZ INF OSEC I NFO --------------------------------

SEEMEI NMALL Best feature is that same plaintext character is substituted by different cipher text characters (i.e., Polyalphabetic) Cryptanalysis: The Vigenère cipher might first have been broken by the English mathematician Charles Babbage (1792 – 1871); Kahn quotes Babbage as saying “an indistinct glimpse of defeating it presented itself vaguely to my imagination.” But, if Babbage had a solution, he never published it. Babbage apparently had the tendency to never be satisfied with a work and to continue to refine things; so, he might never have been satisfied enough with his solution to publish it. Friedrich Kasiski (1805 – 1881) is credited with breaking the Vigenère cipher in 1863. From the Sixteenth Century until the Nineteenth Century the cipher was generally considered to be secure. We will use Kasiski’s technique to determine the length of the keyword. In the Twentieth Century, William Frederick Friedman (1891 – 1969), the dean of American cryptologists, developed a statistical method to estimate the length of the keyword.

Beale cipher:
It is also known as book cipher. Keyword is taken as the first few words of a book that is agreed upon by sender and receiver. Everything else works like the Vigenère cipher.

Vernam cipher:
U.S. Army Major Joseph Mauborgne and AT&T’s Gilbert Vernam developed a cipher in 1917 Uses a onetime arrangement of a key string that is as long as the plaintext Plaintexts are assumed to be short Also known as One-Time Pad cipher Key is used only once but characters in key may not be distinct. E.g., Plaintext: HELLO Key: KTBXZ Cipher text: RXMIN (using addition mod 26) Key: KTBXZ Received: RXMIN Plaintext: HELLO (using subtraction mod 26) Cryptanalysis: If a truly random key as long as the message is Used, the cipher will be secure - One-Time pad • E.g., a random sequence of 0’s and 1’s XORed toPlaintext, no repetition of keys

• Unbreakable since cipher text bears no statistical relationship to the plaintext • For any plaintext, it needs a random key of the same length Hard to generate large amount of keys. • Have problem of safe distribution of key

Conclusion
Based on the network requirements and the other criteria the substitution cipher cryptography algorithms are used .The cryptanalysis of these algorithms are used to compare the various types. And based on it the new algorithms are invented by taking care of the disadvantages of their predecessors.

References
1. http://en.wikipedia.org/wiki/Monoalphabetic_cipher 2. http://en.wikipedia.org/wiki/Monoalphabetic_cipher#Polygraphic_substitution 3. http://en.wikipedia.org/wiki/Cipher 4. http://www.nku.edu/~christensen/section%2012%20vigenere%20cryptanalysis.pdf 5. http://math.boisestate.edu/~liljanab/MATH509Spring2012/CryptanalysisSubstitutionCiphe r.pdf 6. http://www.rimtengg.com/iscet/proceedings/pdfs/misc/20.pdf 7. http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.55.89

Similar Documents

Free Essay

Performance Analysis of Substitution Cipher Based Cryptographic Algorithm

...CURRICULUM VITAE EGUNSOLA Olubola Kehinde 16, Adeolu Egunsola Street Off Jibowu Estate Road U-Turn Bus Stop Abule-Egba Lagos. PERSONAL PORTFOLIO Date of Birth 17th August 1972 Place of Birth Lagos State State of Origin Ogun State Nationality Nigerian L.G.A Abeokuta South Sex Male Marital Status Married Number of Child. Three Children, 8yrs, 5yrs, and 3yrs old E-Mail egunsola_olubola @yahoo.com Phone Number 08035855769 07086566947 Permanent Address 10, Ogere Road, Iperu-Remo, Ogun State. EDUCATIONAL BACKGROUND Institution Certificate Date Federal University of Technology M.Tech 2010-2013 Yola, Adamawa State Operations Research option(Computer Simulation) Olabisi Onabanjo University Ago Iwoye B.Sc (Ed) 1997-2000 (Formerly Ogun State University) Computer Science Federal College of Education Osiele N.C.E 1994-1996 Abeokuta Ogun State Computer Science/PSC Egbado College Ilaro ...

Words: 1309 - Pages: 6

Free Essay

General Introductio

...NATIONAL UNIVERSITY OF RWANDA FACULTY OF APPLIED SCIENCES DEPARTMENT OF COMPUTER SCIENCE ACADEMIC YEAR 2011 Performance analysis of Encryption/Decryption algorithms using SimpleScalar By: MANIRIHO Malachie and NIZEYIMANA Jean-Paul Supervisor: Dr.-Ing. NIYONKURU Adronis Huye, 2011 CHAPTER ONE: GENERAL INTRODUCTION 1.1. BACKGROUND TO THE STUDY There are various security measures that can be imposed in order to secure the information stored. As more and more technologies evolve, an irresponsible person may try to find a way to excavate any loopholes within the system in order to penetrate into the heart of its weaknesses. This is due to the fact that human-made designs can also be broken by another human. Thus, over time security measures must constantly be reviewed and strengthened in order to combat hackers or culprits hot on the heels of system developers who are also using high technologies. One of the means to secure the data is to apply a secret code of encryption. By having it encrypted, the sender can pass the data to the receiver and only the receiver or authorized personnel can have access to the data provided they have been given a key by the sender to decrypt it in order for them to view the information. Thus, without having the right key, nobody is able to read the encrypted data received or stored. Even if hackers or unauthorized person managed to intercept or steal the data, it would be...

Words: 7475 - Pages: 30

Premium Essay

Importance Of Cryptography

...necessary to know the method of securing data transmission by Cryptographic technique. 1.2 THE PURPOSE OF CRYPTOGRAPHY Cryptography is among one of the ancient arts of writing languages in secret code. In 1900 B.C an Egyptian scribe was the first document used inscription for cryptography. Some of the experts argued that cryptography writing has appeared simultaneously after the writing has been invented,...

Words: 10253 - Pages: 42

Free Essay

Partial Encryption on Fly

...A NOVEL APPROACH TO IMPLEMENT DISK SECURITY USING PARTIAL DISK ENCRYPTION Anurag Sharma M L Smitha Tarun T Arya Minal Moharir Information Science and Engineering RV College of Engineering The main objective of the paper is to develop an efficient and cost effective method for Hard Disk Drive(HDD) Security. The task is implemented using Partial Disk Encryption (PDE) with Advanced Encryption Standards(AES) for data security of Personal Computers(PCS) and Laptops . The focus of this work is to authenticate and protect the content of HDD from illegal use. The proposed method is labeled as DiskTrust. FDE encrypts entire content or a single volume on your disk. Symmetric key uses same key for encryption as well for decryption. DiskTrust uses these two technology to build cost effective solution for small scale applications. Finally, the applicability of these methodologies for HDD security will be evaluated on a set of data files with different key sizes. KEYWORDS- INFORMATION SECURITY, INTEGRITY, CONFIDENTIALITY, AUTHENTICATION, ENCRYPTION. I. INTRODUCTION In today’s world information security is an important concern for every individual. People spend hundreds of dollars in protecting their data to stay in the competition, and any leakage of crucial data can result in unrecoverable loss. Information security is the most important form of security even before network security, as information stored securely can only be transmitted securely over a network, there......

Words: 2258 - Pages: 10

Premium Essay

Some Problems in Symmetric and

...Some Problems in Symmetric and Asymmetric Cryptography A thesis submitted for the partial fulfillment of the degree of Doctor of Philosophy in Mathematics By SANTOSH KUMAR YADAV Under the supervision of Prof. Sunder Lal and Prof. S. C. Arora DEPARTMENT OF MATHEMATICS DR. B. R. AMBEDKAR UNIVERSITY, AGRA (FORMERLY AGRA UNIVERSITY) 2010 *Sanskrit verse dating back to the pre-Christian era Dedicated to my Teachers, Friends, Students and Family Members DECLARATION I do hereby declare that the present research work has been carried out by me under the supervision of Prof. Sunder Lal and Prof. S. C. Arora. This work has not been submitted elsewhere for any other degree, diploma, fellowship or any other similar title. Santosh Kumar Yadav Research Scholar CERTIFICATE This is to certify that the thesis entitled “Some Problems in Symmetric and Asymmetric Cryptography” submitted to Dr. B.R.Ambedkar University, Agra for the degree of Doctor of Philosophy by Mr. Santosh Kumar Yadav, is a bonafide record of research work done by him under our supervision. To the best of our knowledge, this thesis has not previously formed the basis for the award to any candidate of any degree, diploma, fellowship or any other similar title and the work has not been submitted to any university or institution, for the award of any other degree. S. C. ARORA SUNDER LAL (Co-supervisor) (Supervisor) Professor Professor of Mathematics, and Department of Mathematics Pro-Vice......

Words: 37424 - Pages: 150

Free Essay

Digital Forensics - Uganda’s Preparedness

...Digital Forensics: Uganda’s Preparedness Dennis Tusiime Rwatooro 2014-M142-2002 Dept of Computer Science Abstract — The more our lives continue to depend on digital communication networks and media to perform daily activities such as communication, access to information and critical services such as health, financial transactions, entertainment, and public utilities like electricity, the more we get exposed to security risks. These security risks include breach of confidentiality of communication and transactions, violation of personal privacy, crime and fraud, disruption of services, and distribution of inappropriate content, among others. The goal of digital security is to research into and develop mechanisms to address these security risks. In this paper we briefly survey some of the emerging issues in digital security. The literature shows that while some domains in digital security have remained unchanged over a long time, for example cryptography, new areas have emerged including steganography. Keywords – digital forensic techniques, volatitle data extraction, digital image forensics, malware investigations, email security, symmetric key cryptography, asymmetric key cryptography, public key cryptography. Introduction Forensic science is defined as the application of the sciences as it pertains to legal matters or problems (Gialamas, 2000). One of the branches/fields of forensic science, namely criminalistics, is the profession and scientific discipline......

Words: 7291 - Pages: 30

Premium Essay

Pretty Good Privacy

...secure web services grows. There are two types of threats to the web services : 1.1 Passive attacks : It is eavesdropping on network traffic between browser and server and gaining access to information on a web site that is supposed to be restricted. 1.2 Active attack : It includes impersonating another user, altering messages in transit between client and server and altering information on a web site. In all distributed environment electronic mail is the most heavily used network based application. It is the only application that is widely used across all architecture and vendor platforms. Users expect to be able to and do, send mail to others who are connected directly or indirectly to the internet. PGP(Pretty Good Privacy) is an open-source freely available software for E-Mail security. It provides authentication through the use of digital signature, confidentiality through the use of symmetric block encryption, compression using the ZIP algorithm, E-Mail compatibility using the radix-64 encoding scheme and segmentation and reassembly to accommodate long e-mails. Chapter 2 Review of literature tells the need and appraisal of e-mail security Software. E-mail is well established as a prime means of communication for business purposes that is quicker and cheaper than more traditional methods. Thus is necessary to make one’s corporate messaging system as secure as...

Words: 27771 - Pages: 112

Premium Essay

Crhypho

...ws@shore.net. An errata sheet for this manual, if needed, is available at ftp://shell.shore.net/members/w/s/ws/S. W.S. -4- TABLE OF CONTENTS Chapter 1: Chapter 2: Chapter 3: Chapter 4: Chapter 5: Chapter 6: Chapter 7: Chapter 8: Chapter 9: Chapter 10: Chapter 11: Chapter 12: Chapter 13: Chapter 14: Chapter 15: Chapter 16: Chapter 17: Chapter 18: Chapter 19: Chapter 20: Introduction ..................................................................................................5 Classical Encryption Techniques ...............................................................7 Block Ciphers and the Date Encryption Standard ................................13 Finite Fields .................................................................................................21 Advanced Encryption Standard ..............................................................28 More on Symmetric Ciphers ....................................................................33 Confidentiality Using Symmetric Encryption .......................................38 Introduction to Number Theory ..............................................................42 Public-Key Cryptography and RSA...

Words: 21497 - Pages: 86

Premium Essay

Sscp Study Notes

...SSCP Study Notes 1. Access Controls 2. Administration 3. Audit and Monitoring 4. Risk, Response, and Recovery 5. Cryptography 6. Data Communications 7. Malicious Code Modified version of original study guide by Vijayanand Banahatti (SSCP) Table of Content 1.0 ACCESS CONTROLS…………………………………………………………...... 03 2.0 ADMINISTRATION ……………………………………………………………... 07 3.0 AUDIT AND MONITORING…………………………………………………...... 13 4.0 RISK, RESPONSE, AND RECOVERY………………………………………....... 18 5.0 CRYPTOGRAPHY……………………………………………………………....... 21 6.0 DATA COMMUNICATIONS…………………………………………………...... 25 7.0 MALICIOUS CODE……………………………………………………………..... 31 REFERENCES………………………………………………………………………........ 33 1.0 ACCESS CONTROLS Access control objects: Any objects that need controlled access can be considered an access control object. Access control subjects: Any users, programs, and processes that request permission to objects are access control subjects. It is these access control subjects that must be identified, authenticated and authorized. Access control systems: Interface between access control objects and access control subjects. 1.1 Identification, Authentication, Authorization, Accounting 1.1.1 Identification and Authentication Techniques Identification works with authentication, and is defined as a process through which the identity of an object is ascertained. Identification takes place by using some form of authentication. Authentication Types Example Something you know...

Words: 17808 - Pages: 72

Free Essay

التشفير وأمنية المعلومات

...الفصل الأول التعريف بتقنيات التشفير وأمنية المعلومات 1-1:المقدمة ( Introduction ): إن أمنية المعلومات ناتجة من الحاجة إلى تناقل المعلومات الخاصة لكل من العبارات العسكرية والدبلوماسيـة. هذه الحاجة هي قديمة بقدم الحضارة نفسها. الأسبان القدماء مثلا, شفروا عباراتهم العسكرية. أما بالنسبة للصين, فانه يكفي فقط كتابة العبارات بلغتهم المعروفة والتي تعبر لغة خاصة, وذلك لان القليل من الناس يستطيعون قراءة الحروف الصينية. كانت قنوات الاتصال في السابق بسيطة جدا وكانت ترتب بأسلوب يعتمد في تامين السري على استخدام مراسلين موثوقين. تعتمد الأمنية لمثل هذا التنظيم على كل من موضع الثقة للمراسل وقابليته في أن يبقى محتفظا بالمواقف أو المواقع التي فيها يمكن أن تتعرض العبارات للانتهاك. بسبب اكتشاف أنظمة الحاسبات واستخدام شبكات الحاسبة الواسعة بين الدول, فان القرن العشرين قد غير بصورة ملحوظة مدى مفاهيم الحماية. في الحاسبات المبكرة ( الأولى), فان الأمنية الفيزيائية ومعها سياسة الاختيار الملائم للكادر العامل في الحاسبة كان كافيا لتامين الأمنية. لكن هذا أصبح غير كاف وغير مرن بعد اكتشاف أنظمة حاسبات المشاركة الزمنية (Time-Sharing) والتي تتألف من عدة محطات طرفية موزعة في مساحة جغرافية واسعة. من الجدير بالذكر أن امن وسلامة اتصال,ت الالكترونية في بدء ظهورها لم يكن هاما لان معظم المعلومات المخزونة فيها لم تكن ذات حساسية كبيرة, بعكس ماهي عليه اليوم, إذ كلما ازدادت وارتفعت قيمة المعلومات المخزونة في الحاسبات الالكترونية كلما ازدادت الرغبة لدى بعض الأفراد لمحاولة الوصول إليها من اجل التخريب أو من اجل الكسب غير المشروع بواسطة بيعها إلى الجهات الراغبة بذلك, لذا فقد أصبح امن هذه المعلومات على......

Words: 35136 - Pages: 141

Premium Essay

Syllabus

...Code 1. 2. 3. 4. 5. 6. CSE411 CSE461 CSE412 CSE462 CSE414 CSE464 Subject Title Scheme of Teaching L 3 0 3 0 3 0 T 1 0 1 0 1 0 P 0 3 0 3 0 3 Hours 4 3 4 3 4 3 Credit 4 2 4 2 4 2 University External Marks 50 50 50 CSE361 CSE313 CSE363 AS301 EC316 EC366 EC317 EC367 Data Structures (Practical) Peripheral Devices & Interfaces Hardware Lab (Practical) Engineering Mathematics – III Digital Electronics Digital Electronics (Practical) Microprocessors Microprocessors (Practical) 0 3 0 3 3 0 3 0 15 0 1 0 1 1 0 1 0 5 3 0 2 0 0 2 0 2 09 3 4 2 4 4 2 4 2 29 2 4 1 4 4 1 4 1 25 50 50 50 50 250 Internal Total Sessional Marks 50 50 50 50 50 50 50 50 50 450 100 50 100 50 100 100 50 100 50 700 7. 8. Total ASC405 CSE 415 Analysis & Design of Algorithms Analysis & Design of Algorithms (Practical) Database Management System Database Management System (Practical) Object Oriented Programming Object Oriented Programming (Practical) Cyber Law & IPR Computer Architecture & Organization Internal Total Sessional Marks 50 100 50 50 50 50 50 50 100 50 100 50 3 3 15 0 1 4 0 0 9 3 4 28 3 4 25 50 50 250 50 50 400 100 100 650 2 Scheme of Examination of B.E. in Computer Science & Engineering Third Year - Fifth Semester Sr. Paper Subject Title Scheme of Teaching Univesity Internal Sessional Code External L T P Hou Credit Marks Total Marks rs s 1. CSE511 Operating System 3 1 0 4 4 50 50...

Words: 14784 - Pages: 60

Free Essay

Innovation and Erp Systems

...Scheme and Syllabus of B.E. (Computer Science and Engineering) 3 rd th TO 8 Semester 2014-2015 University Institute of Engineering and Technology, Panjab University, Chandigarh DEPARTMENT: COMPUTER SCIENCE AND ENGINEERING VISION: To be recognized as an international leader in Computer Science and Engineering education and research to benefit society globally. MISSION: · · · · To move forward as frontiers of human knowledge to enrich the citizen, the nation, and the world. To excel in research and innovation that discovers new knowledge and enables new technologies and systems. To develop technocrats, entrepreneurs, and business leaders of future who will strive to improve the quality of human life. To create world class computing infrastructure for the enhancement of technical knowledge in field of Computer Science and Engineering. PROGRAMME: B.E. CSE (UG PROGRAMME) PROGRAMME EDUCATIONAL OBJECTIVES: I. Graduates will work as software professional in industry of repute. II. Graduates will pursue higher studies and research in engineering and management disciplines. III. Graduates will work as entrepreneurs by establishing startups to take up projects for societal and environmental cause. PROGRAMME OUTCOMES: A. Ability to effectively apply knowledge of computing, applied sciences and mathematics to computer science & engineering problems. B. Identify, formulate, research literature, and analyze complex computer science & engineering problems reaching substantiated......

Words: 23989 - Pages: 96

Premium Essay

Netwrk Security

...Fundamentals of Network Security John E. Canavan Artech House Boston • London http://www.artechhouse.com Library of Congress Cataloging-in-Publication Data Canavan, John E. Fundamentals of network security / John E. Canavan. p. cm.—(Artech House telecommunications library) Includes bibliographical references and index. ISBN 1-58053-176-8 (alk. paper) 1. Computer security. 2. Computer networks—Security measures. I. Title. II. Series. QA76.9.A25 C364 2000 005.8—dc21 00-050810 CIP British Library Cataloguing in Publication Data Canavan, John E. Fundamentals of network security.—(Artech House telecommunications library) 1. Computer networks—Security measures I. Title 005.8 1-58053-176-8 Cover design by Yekaterina Ratner Microsoft ® screen shots reprinted by permission from Microsoft Corporation. Netscape Communicator browser window © 1999 Netscape Communications Corporation. Used with permission. Netscape Communications has not authorized, sponsored, endorsed, or approved this publication and is not responsible for its content. Permission to reproduce screen shots from the PGP and Sniffer products has been provided by Network Associates, Inc. Network Associates, PGP, Pretty Good Privacy Sniffer, and Distributed Sniffer System are registered trademarks of Network Associates, Inc. and/or its affiliates in the U.S. and/or other countries. MIT screen shots used with permission. Qualcomm's Eudora screen shots used with permission. Copyright © 2001 ARTECH HOUSE, INC. 685 Canton......

Words: 95027 - Pages: 381

Premium Essay

Paper

...Management of Information Security Third Edition This page intentionally left blank Management of Information Security Third Edition Michael Whitman, Ph.D., CISM, CISSP Herbert Mattord, M.B.A., CISM, CISSP Kennesaw State University ———————————————————————— Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Management of Information Security, Third Edition Michael E. Whitman and Herbert J. Mattord Vice President, Career and Professional Editorial: Dave Garza Executive Editor: Stephen Helba Managing Editor: Marah Bellegarde Product Manager: Natalie Pashoukos Developmental Editor: Lynne Raughley Editorial Assistant: Meghan Orvis Vice President, Career and Professional Marketing: Jennifer McAvey Marketing Director: Deborah S. Yarnell Senior Marketing Manager: Erin Coffin Marketing Coordinator: Shanna Gibbs Production Director: Carolyn Miller Production Manager: Andrew Crouth Senior Content Project Manager: Andrea Majot Senior Art Director: Jack Pendleton Cover illustration: Image copyright 2009. Used under license from Shutterstock.com Production Technology Analyst: Tom Stover © 2010 Course Technology, Cengage Learning ALL RIGHTS RESERVED. No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Web distribution,......

Words: 229697 - Pages: 919

Free Essay

Ethical Hacking

...This page was intentionally left blank This page was intentionally left blank Hands-On Ethical Hacking and Network Defense Second Edition Michael T. Simpson, Kent Backman, and James E. Corley ———————————————————————— Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. This is an electronic version of the print textbook. Due to electronic rights restrictions, some third party content may be suppressed. Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. The publisher reserves the right to remove content from this title at any time if subsequent rights restrictions require it. For valuable information on pricing, previous editions, changes to current editions, and alternate formats, please visit www.cengage.com/highered to search by ISBN#, author, title, or keyword for materials in your areas of interest. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or......

Words: 185373 - Pages: 742