TweetFollow Us on Twitter

Oct 99 Bookshelf

Volume Number: 15 (1999)
Issue Number: 10
Column Tag: Programmer's Bookshelf

Review: Cryptography and Network Security

by Paul E. Sevinc, Switzerland

Principles and Practice, 2nd edition

Cryptology is a topic more and more people in the IT business have to be familiar with. If you already know the basics and only need a reference manual so to speak, choosing the right book is easy: [Menezes et al. 1997]. But if you're looking for an introductory text book, you have an ordeal of choice. One book you'll often see recommended is [Schneier 1996]. In this article we're going to take a closer look at another one, namely the 2nd edition of Cryptography and Network Security: Principles and Practice [Stallings 1999].

The Big Picture

Cryptography and Network Security (CaNS for short) has been published by Prentice Hall and was written by William Stallings, an author with quite an impressive publication list (see <http://www.prenhall.com/stallings/>). Besides, famous cryptographers like Xuejia Lai, Ron Rivest, Phil Zimmermann and many others reviewed Stallings' treatment of their special fields. In my opinion, this makes the book very trustworthy.

Between the introduction and the appendix (for teachers), CaNS is organized in four parts: Conventional Encryption, Public-Key Encryption and Hash Functions, Network Security Practice, and System Security. The introduction discusses network security models and computer security threats, thereby motivating the remainder of the text.

From the very beginning, it is obvious that CaNS is not intended to be a popular-science book but rather for (prospective) scientists and engineers.

Conventional Encryption

The first part, chapters 2 to 5, deals with symmetric cryptography, i.e. schemes in which the same key is used for both encryption and decryption. Actually, the main focus is on so-called block ciphers while stream ciphers are hardly an issue. (There are two ways how to use block ciphers as stream ciphers, though, and Stallings explains both when he treats the four block-cipher modes of operation.) The math used in this part ñmodular arithmetic, linear equations, matricesñ should be basic to most programmers.

Chapters 2 & 3 treat the building blocks of both classical and modern symmetric algorithms and show how these are used within DES, the Data Encryption Standard. With the exception of the one-time pad, the classical algorithms are nowadays insecure, but still interesting for more than just historical reasons. Chapter 3 ends with general design principles of and attacks on block ciphers. I find this to be useful to practitioners who have to decide on and implement an algorithm, not to hackers :-)

Unless interested in details of different algorithms currently in use, the reader can safely skip most of chapter 4. Nevertheless, the first section is important because it contains information about the Men-in-the-Middle attack, and the last section is a good summary of the rest of the chapter.

Most of us don't really need to know how exactly encryption works. But if we use it, we better use it right. In chapter 5, Stallings explains where and how symmetric schemes can be used in an internetwork, including the non-trivial task of key distribution. One problem in this context is generating good pseudo-random numbers. Different approaches are mentioned, but only very briefly.

Public-Key Encryption and Hash Functions

The second part, chapters 6 to 10, deals with functions that map variable-length data into a fixed-length value and with asymmetric cryptography, i.e. schemes in which different keys are used for encryption and decryption. This part is more mathematical than the last as public-key cryptosystems are heavily based on number theory, the subject of chapter 7. (Stallings only introduces what is necessary for understanding CaNS. If you're not familiar with number theory, I suggest you read this chapter before the 6th.)

Starting with the principles of public-key cryptography, chapter 6 presents RSA, the Rivest-Shamir-Adleman algorithm, the Diffie-Hellman key-exchange protocol, and key-management issues in general. At the end of this chapter, there's a short section about elliptic-curve cryptography, a hot topic of growing importance, which I highly appreciated.

Similar to chapters 3 & 4, chapter 8 first treats requirements and design principles of, as well as attacks on cryptographic hash functions and message authentication codes (key-dependent hash functions so to speak), and then chapter 9 describes four concrete algorithms in detail: MD5, SHA-1, RIPEMD-160 (that's what I call an acronym!), and HMAC.

Chapter 10 concludes the second part with a discussion of authentication protocols and digital signatures. The former include such based on symmetric cryptography, the latter DSS, the Digital Signature Standard.

Network Security Practice

The chapters in the third part (11-14) can be consulted in any order the reader likes. The prerequisites have been covered in the first two parts. This part is a nice add-on to older, in terms of IT years, computer-network books that don't cover network security (in enough detail). It includes sections on Kerberos, X.509, PGP, S/MIME, IPSec, SSL/TLS, and SET.

Kerberos and X.509 are for authentication purposes. PGP, Pretty Good Privacy, and S/MIME, Secure/Multipurpose Internet Mail Extensions, provide e-mail security. IPSec comprises the security features that have been defined for IPv6, but that can also be used with IPv4. (Those of you familiar with IP, the Internet Protocol, know that we're currently making the [slow] transition from IPv4 to IPv6.) SSL is Netscape's Secure Socket Layer which has become Transport Layer Security, an Internet standard. Finally, SET, Secure Electronic Transaction, is a specification initiated by MasterCard and Visa for credit-card payments over the internet.

By carefully reading several of these case studies, one gets a good idea of the trade-offs (e.g., security vs. complexity) involved in the design of cryptographic protocols. This is supported by Stallings' clear and concise writing and his judicious use of figures and tables.

System Security

The last part, chapters 15 & 16, is very high-level and easy to understand. However, it only provides an overview and can't replace an in-depth (and more technical) treatment of the same topics.

I was blown away by chapter 15. It is about intruders (i.e., hackers and crackers) and malicious programs, especially viruses. The many ñsometimes ingeniousñ ways of attacking a computer system and their countermeasures make for very exciting reading; look forward to a rainy Sunday!

Chapter 16 is a short chapter about the principles and goals underlying firewalls. It ends with a section on so-called trusted systems and how these can be used to defend against trojan horses.

Conclusion

CaNS is a very good introduction to cryptography, enabling you to understand and discuss the security of practical cryptosystems (e.g., the Mac OS keychain). But if you intend to develop or consult on cryptosystems yourself, you need to know more about number and information theory (see the seminal [Shannon 1948]) than is covered by Stallings. The parts about network and system security are good, too, even though they might not be applied enough for some readers (e.g., system administrators).

Every chapter ends with a set of non-trivial problems (the solutions are not part of the book). Some chapters additionally feature an appendix of their own, for example about ZIP's compression algorithm, the Birthday paradox, IPv4 and IPv6, etc. These appendices increase CaNS' usefulness and are thus worth being studied.

Finally, a five-page glossary and a one-page list of acronyms conclude this highly recommendable book.

Acknowledgments

I would like to thank Neso Atanasoski for his comments on this article and Andrew S. Downs for his editing of my Core Java review (May issue). Sorry for the delay, Andrew!

References

  • [Menezes et al. 1997] MENEZES, Alfred J., VAN OORSCHOT Paul C., VANSTONE, Scott A. ñ Handbook of Applied Cryptography, CRC Press, 1997.
  • [Schneier 1996] SCHNEIER, Bruce. ñ Applied Cryptography, Wiley, 2nd ed. 1996.
  • [Shannon 1948] SHANNON, Claude E. ñ A Mathematical Theory of Communication, pp. 379-423 (623-656) in: The Bell System Technical Journal, volume 27, July (October) 1948.
  • [Stallings 1999] STALLINGS, William. ñ Cryptography and Network Security: Principles and Practice, Prentice Hall, 2nd ed. 1999.

Paul is an EE student at the Swiss Federal Institute of Technology Zurich (ETHZ) where he might spend another three years if he accepts the Ph.D. position offered to him. But as he feels like living in the US for some time, he's wondering whether he should rather join a R&D department in Silicon Hills or Silicon Valley. While he's thinking about this, visit his homepage at http://www.stud.ee.ethz.ch/~psevinc/.

 
AAPL
$524.94
Apple Inc.
+5.93
MSFT
$40.01
Microsoft Corpora
-0.39
GOOG
$536.10
Google Inc.
-20.44

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mac DVDRipper Pro 4.1.7 - Copy, backup,...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
PDFpenPro 6.2 - Advanced PDF toolkit for...
PDFpenPro allows users to edit PDF's easily. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Create... Read more
PDFpen 6.2 - Edit and annotate PDFs with...
PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Features... Read more
Monolingual 1.5.9 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
Maya 2015 - Professional 3D modeling and...
Maya is an award-winning software and powerful, integrated 3D modeling, animation, visual effects, and rendering solution. Because Maya is based on an open architecture, all your work can be scripted... Read more
Starcraft II: Wings of Liberty 1.1.1.180...
Download the patch by launching the Starcraft II game and downloading it through the Battle.net connection within the app. Starcraft II: Wings of Liberty is a strategy game played in real-time. You... Read more
Sibelius 7.5.0 - Music notation solution...
Sibelius is the world's best-selling music notation software for Mac. It is as intuitive to use as a pen, yet so powerful that it does most things in less than the blink of an eye. The demo includes... Read more
Typinator 5.9 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
MYStuff Pro 2.0.16 - Create inventories...
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more
TurboTax 2013.r17.002 - Manage your 2013...
TurboTax guides you through your tax return step by step, does all the calculations, and checks your return for errors and overlooked deductions. It lets you file your return electronically to get... Read more

Latest Forum Discussions

See All

Trials Frontier Review
Trials Frontier Review By Carter Dotson on April 18th, 2014 Our Rating: :: A ROUGH LANDINGUniversal App - Designed for iPhone and iPad Trials Frontier finally brings the famed stunt racing franchise to mobile, but how much does its... | Read more »
Evernote Business Notebook by Moleskin I...
Evernote Business Notebook by Moleskin Introduced – Support Available in Evernote for iOS Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
Sparkle Unleashed Review
Sparkle Unleashed Review By Jennifer Allen on April 18th, 2014 Our Rating: :: CLASSY MARBLE FLINGINGUniversal App - Designed for iPhone and iPad It’s a concept we’ve seen before, but Sparkle Unleashed is a solidly enjoyable orb... | Read more »
Tilt to Live 2: Redonkulus Receives its...
Tilt to Live 2: Redonkulus Receives its First Update – Gets New Brimstone Pinball DLC Posted by Rob Rich on April 18th, 2014 [ permalink ] | Read more »
Union Review
Union Review By Jennifer Allen on April 18th, 2014 Our Rating: :: LAYERED RESULTSUniversal App - Designed for iPhone and iPad Create some stylish imagery with this layers focused photography app.   | Read more »
Where's My Water? Featuring XYY (G...
Where's My Water? Featuring XYY 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: iPod Touch 4th Gen, iPhone 3GS or iPad 1 are not compatible with this app. | Read more »
The Amazing Spider-Man 2 (Games)
The Amazing Spider-Man 2 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: *IMPORTANT* The Amazing Spider-Man 2 requires an iPad 2 (or newer), iPhone 4s (or newer), or iPod touch 5th... | Read more »
Living Planet - Tiny Planet Videos and P...
Living Planet - Tiny Planet Videos and Photos 1.0 Device: iOS Universal Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: 50% OFF LAUNCH SPECIAL! BUY NOW BEFORE THE PRICE GOES UP... | Read more »
Livescribe 3 Smartpen Review
Made by: Livescribe Price: $149.99 for Livescribe 3 Hardware/iOS Integration Rating: 4.5 out of 5 stars Usability Rating: 4 out of 5 stars Reuse Value Rating: 4.75 out of 5 stars Build Quality Rating: 4.5 out of 5 stars Overall Rating: 4.44 out of... | Read more »
Unpossible Review
Unpossible Review By Carter Dotson on April 17th, 2014 Our Rating: :: RALPH WIGGUM APPROVESUniversal App - Designed for iPhone and iPad Unpossible is much better than its English!   | Read more »

Price Scanner via MacPrices.net

iMacs on sale for up to $160 off MSRP this we...
Best Buy has iMacs on sale for up to $160 off MSRP for a limited time. Choose free home shipping or free instant local store pickup (if available). Prices are valid for online orders only, in-store... Read more
iPad Airs on sale this weekend for up to $100...
Best Buy has WiFi iPad Airs on sale for $50 off MSRP and WiFi + Cellular iPad Airs on sale for $100 off MSRP on their online store for a limited time, with prices now starting at $449. Choose free... Read more
Apple restocks refurbished Mac minis starting...
The Apple Store has restocked Apple Certified Refurbished Mac minis for up to $150 off the cost of new models. Apple’s one-year warranty is included with each mini, and shipping is free: - 2.5GHz Mac... Read more
Hyundai Brings Apple CarPlay To The 2015 Sona...
Hyundai Motor America has announced it will bring Apple CarPlay functionality to the 2015 Sonata. CarPlay is pitched as a smarter, safer and easier way to use iPhone in the car and gives iPhone users... Read more
Updated iPads Coming Sooner Than We Had Thoug...
MacRumors, cites KGI securities analyst Ming Chi Kuo, well-respected as an Apple product prognisticator, saying that Apple will introduce an upgraded iPad Air and iPad mini in 2014/Q3, meaning the... Read more
Toshiba Unveils New High And Low End Laptop M...
Toshiba has announced new laptop models covering both the high-end and low-end of the notebook computer spectrum. Toshiba 4K Ultra HD Laptop Toshiba’s new Satellite P55t features one of the world’s... Read more
Save up to $270 with Apple refurbished 13-inc...
The Apple Store has Apple Certified Refurbished October 2013 13″ Retina MacBook Pros available starting at $1099, with models up to $270 off MSRP. Apple’s one-year warranty is standard, and shipping... Read more
Apple now offering refurbished iPad mini with...
The Apple Store has Certified Refurbished 2nd generation iPad minis with Retina Displays now available starting at $339. Apple’s one-year warranty is included with each model, and shipping is free.... Read more
Microsoft Blinks – Drops Microsoft Office 365...
Microsoft has dropped the annual subscription fee for Microsoft Office 365 Personal – which is needed in order to create and edit documents in Microsoft Office for iPad. However, Apple’s iOS and OS X... Read more
New AVG Vault Apps for iOS and Android Help K...
AVG Technologies N.V. an online security company for 177 million active users, has announced the launch of its latest mobile application, AVG Vault. The free app introduces an innovative user... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Retail - Manager - Holyoke - Apple I...
Job Summary Keeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you’re a master of them all. In the store’s fast-paced, Read more
*Apple* Retail - Manager - Apple (United Sta...
Job SummaryKeeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you're a master of them all. In the store's fast-paced, dynamic Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Retail - Market Leader - Cincinnati...
…challenges of developing individuals, building teams, and affecting growth across Apple Stores. You demonstrate successful leadership ability - focusing on excellence Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.