Home > Store

.NET Security and Cryptography

Register your product to gain access to bonus material or receive a coupon.

.NET Security and Cryptography


  • Sorry, this book is no longer in print.
Not for Sale


  • Copyright 2004
  • Dimensions: 7" x 9-1/4"
  • Pages: 496
  • Edition: 1st
  • Book
  • ISBN-10: 0-13-100851-X
  • ISBN-13: 978-0-13-100851-9

Part of the Integrated .NET Series, this book provides a practical and comprehensive treatment on implementing both cryptography and security features on the .NET platform using the C# and VB .NET programming languages. It provides focused and detailed code examples that demonstrate the most important concepts, with commentary on how the code examples work. The book also provides a substantial mathematical and theoretical background on the underlying cryptographic concepts. After reading this book and experimenting with the provided example programs, the reader should have a good understanding of the major cryptographic algorithms and standard cryptographic programming techniques. Readers should also gain a solid understanding of how .NET security works and how to implement user-based and code access security in their own .NET programs.

Sample Content

Online Sample Chapter

Asymmetric Cryptography

Table of Contents



About This Series.

1. NET Cryptography and Security.

The Nature of This Book. Risks Are Everywhere. The Nature of Cryptography and Security. Why Cryptography and Security Are Important. What Cryptography and Security Can and Cannot Do. Windows Security Comes of Age. The .NET Framework and the CLR. How the .NET Framework Simplifies Security. Reliability and the .NET Platform. Managed Code and Type Safety. .NET Cryptography Programming. .NET Security Programming. Role-Based Security and Principals. CAS, Evidence, Policy, and Permissions. Summary.

2. Fundamentals of Cryptography.

Security and Keeping Secrets. Basic Cryptographic Terminology. Secret Keys Versus Secret Algorithms. Classical Techniques for Keeping Secrets. Brute-Force Attack Work Factor. Arbitrary Precision Arithmetic. Steganography. Modern Ciphers. Cryptography and the .NET Framework. Symmetric Cryptography. Asymmetric Cryptography. Cryptographic Algorithms. Cryptographic Protocols. Cryptanalytic Attacks. Issues in Human Interaction and Trust. Risk and Benefit. Other Important Concepts. Summary.

3. Symmetric Cryptography.

Symmetric Ciphers. DES. Modes of Operation. Triple DES. Rijndael. RC2. Programming with .NET Symmetric Cryptography. The Main Cryptography Classes. The SymmetricAlgorithm Class. SymmetricAlgorithm-Derived Classes. The SymmetricAlgorithms Example. Cryptographic Streams. Avoiding Weak Keys. Key Exchange Issues. Encrypted Hash Codes and Message Integrity. Keyed Hash Functions and Message Integrity. Summary.

4. Asymmetric Cryptography.

Problems with Symmetric Algorithms. The Key Exchange Problem. The Trust Problem. The Idea Behind Asymmetric Cryptography. Using Asymmetric Cryptography. The Combination Lock Analogy. Trapdoor One-Way Functions. Advantages of the Asymmetric Approach. Combining Asymmetric and Symmetric Algorithms. Existing Asymmetric Algorithms. RSA: The Most Used Asymmetric Algorithm. Underpinnings of RSA. A Miniature RSA Example. Caveat: Provability Issues. Programming with .NET Asymmetric Cryptography. An RSA Algorithm Example. Saving Keys as XML. Digital Certificates. Summary.

5. Digital Signatures.

Hash Algorithms. Good Hash Function Characteristics. Hash Algorithms Provided by .NET. The HashAlgorithm Class. The MD5 and SHA Classes. The KeyedHashAlgorithm Class. Object Identifiers. How Digital Signatures Work. RSA Used as a Digital Signature Algorithm. An RSA Signature Example Program. The Digital Signature Algorithm. Some Mathematical Background: Group Theory. The Discrete Logarithm Problem. How DSA Works. The Asymmetric AlgorithmHierarchy Class Hierarchy. The DSACryptoServiceProvider Class. A DSA Programming Example. Summary.

6. XML Cryptography.

XML Encryption. XML Encryption Versus SSL/TLS. The XML Encryption Specification. What XML Encryption Provides. XML Encryption Syntax. How XML Encryption Works. Classes Used in XML Encryption. Communicating Asymmetric Key Information. The XmlEncryption Example. XML Signatures. The XML Signature Specification. What XML Signatures Provide. XML Signature Syntax. Classes Used in XML Signatures. The EnvelopingXmlSignature Example. Combining XML Signing and XML Encryption. Summary.

7. NET User-Based Security.

Authentication and Authorization. .NET Security Model. Administrating Windows Security. Defining Users and Roles on Windows. Defining Shared Folder Permissions on Windows. Defining NTFS Security on Windows. Administrating .NET Security. Permissions. The IPermission Interface. The IPermission Inheritance Hierarchy. The PrincipalPermission Class. User-Based Security. Principal and Identity Objects. The IIdentity Interface. IIdentity Implementation Classes. The GenericIdentity Class. The WindowsIdentity Class. Principal Objects. The IPrincipal Interface. The GenericPrincipal Class. The WindowsPrincipal Class. Two Approaches to User-Based Security. Imperative User-Based Security. Declarative User-Based Security. Credentials. Network Credentials. Security Discipline. Principle of Least Privilege. Establish Security Policy Early. Summary.

8. NET Code Access Security.

The Need for Code Access Security. Cost Versus Risk. The Range of Risks. Assembly Trustworthiness. Risks of Calling into Unmanaged Code. Security, Managed Code, and the CLR. Microsoft Intermediate Language. Verifiably Type-Safe Code. Denying and Demanding Permissions. How CAS Is Used. Flexible Security. The Luring Attack and Walking the Stack. Managing Security Policy with Code Groups. The Basic Concepts of Security Policy Management. Using the .NET Framework Configuration Tool. Using the Caspol.exe Utility. Imperative Versus Declarative CAS. Evidence-Based Security. The Evidence Class. Obtaining the Current Application Domain Evidence. Enumerating Evidence. The WalkingThruEvidence Example. Accessing the WalkingThruEvidence Example Via IIS. Imperative CAS. Code Access Permissions. CodeAccessPermission Derived Classes. The CodeAccessPermission Class. The UrlIdentityPermission Class. Working with Code Access Permissions. Declarative Code Access Permissions. Square Bracket Attribute Declaration Syntax. The URL Identity Permission Attribute. The SecurityAction Class. Permission Requests. The PermissionRequest Example. Permission Sets. The PermissionSet Class. Defining a Permission Set in a Configuration File. Summary.

9. ASP.NET Security.

Fundamental Security Mechanisms. Authentication: Who Are You? Authorization: Are You Allowed to Access This Resource? Impersonation: Application Assumes Client's Identity. Implementing ASP.NET Authentication. ASP.NET Configuration. Facts and Benefits of the ASP.NET Configuration System. Configuration Hierarchy. Description. Forms Authentication. Method 1: Storing Credentials in the Web.config File. Method 2: Storing Credentials in the XML File. The Users.xml File. The login.aspx File. Method 3: Storing Credentials in a Database. Forms Authentication Classes. Passport Authentication. Windows Authentication. Implementing ASP.NET Authorization. File Authorization. URL Authorization. Implementing ASP.NET Impersonation. Summary.

10. Web Services Security.

Basic Techniques in Securing Web Services. Secure Connection. Authentication and Authorization. Authentication Mechanisms for HTTP. Authenticate Web Service Using SOAPHEADER. The SOAP Message Architecture. Creating a Proxy with Visual Studio .NET. XML Security Technologies. Integrity. XML Signature. Data Protection and Privacy. XML Encryption. XML Key Management Specification (XKMS). Security Assertion Markup Lanquage (SAML). Global XML Web Services Architecture (GXA). WS-Security. WS Initial Specifications. Next Steps of Specifications. Why WS-Security? Security Token Propagation. Message Integrity. Message Confidentiality. Organizations Involved. Summary.

A. A Security Attack Example: The Stack Overrun.

B. How the RSA Cipher Works.

Modular Arithmetic. The BigRSA Example Program. The CrackRSAWorkFactorDemo Example Program.

C. Using the GNU GMP Library.

Installing Cygwin. Testing Your Cygwin Installation. Installing GMP. Uninstalling Cygwin.

D. Cryptography and Security Resources.

Background Knowledge and Conceptual Books. Cryptographic Mathematics Books. Implementing Security Guide Books. Human Interest Books on Cryptography. Cryptography News Groups. Useful Cryptographic and Security Web Sites.

E. Exploring Web Services.

Motivation for Web Services. Web Services Definition. Backbones of Web Services. Next Generation of Distributed Computing: Web Services. Benefits of Web Services. ASP.NET Web Services. Web Services Architecture. Code Model for Web Services. Developing a Simple Concatenate Web Service. Concatenate.asmx and Concatenate.asmx.cs. @ WebService Directive. System.Web.Services Namespace. WebServiceAttribute. WebService Class. WebMethod Attribute. Session Management. Protocols. Accessing a Web Service. Generating a Proxy. Creating a Proxy Using Wsdl.exe. Creating a Windows Form Client. Asynchronous Programming in Web Services. Two Asynchronous Methods (Begin and End). Creating an ASP.NET Calculator Web Service. Web Services Are Still Evolving. Summary.



Over the last several years, security and cryptography technologies have been continually increasing in importance to Windows users and software developers. Additionally, in some respects, the security and cryptographic capabilities of 32-bit Windows has reached parity with larger mini and mainframe computing platforms, where security has always been a major priority. Now, with the advent of .NET, these security capabilities have become much easier to implement than ever before. Of course, a significant investment in effort is still required in understanding the concepts and acquiring the skills necessary to leverage the many security features provided by .NET. Indeed, that is exactly what this book is all about. Although much of the same functionality was provided in the form of an arcane Win32 C Windows library, the advent of .NET has made security and cryptography programming much simpler and much more powerful than ever before. The .NET Security Framework provides a powerful set of security and cryptographic classes that are relatively easy to use, and it is this framework that is explored throughout this book.

This book is intended to provide the reader with a practical and comprehensive coverage on implementing both cryptography and security functionality on the .NET platform. It is an effective tutorial, providing a large number of clear and focused code examples.


The book is organized into ten chapters and five appendixes. Chapter 1 introduces the reader to cryptography and security on the .NET platform, and provides a non-technical overview of the topics that will be described in greater detail in subsequent chapters. This first chapter also provides the reasoning behind the layout of the book and how the two main topics of cryptography and security interrelate with one another. The purpose of this chapter is not to provide significant depth or code examples, but rather it is intended to convey conceptual understanding, and to provide an overview of cryptography and security technologies on the .NET platform. Chapter 2 provides a solid theoretical background to enable the reader to gain a deeper insight into all subsequent chapters. The point is made that all security is based on cryptography, and to understand cryptography in a meaningful way, it is necessary to understand several basic theoretical cryptographic concepts first. Chapters 3, 4, 5, and 6 provide detailed hands-on .NET programming examples, using symmetric algorithms, asymmetric algorithms, digital signatures, and XML cryptography, respectively. Chapters 7 and 8 cover .NET programming with user based security and code access security, respectively. Chapters 9 introduces ASP.NET security programming, and Chapter 10 introduces .NET Web Services security programming.

Each aspect of .NET cryptography and security is dealt with in the proper context and sequence, where they will be most relevant and most easily understood. Appendixes describe a few additional topics, such as security attacks and additional cryptography-related mathematical topics.

This book is intended to be a practical tutorial, with many succinct programming examples that focus on specific and individual concepts. Also, the focus of the book is on practical .NET security programming rather on administrative security tasks. This book also provides sufficient background information to enable the reader to clearly see why security and cryptography are critically important to modern software development. The goal is to equip the reader to begin building significant applications using the .NET Security Framework. This book is part of The Integrated .NET Series from Object Innovations and Prentice Hall PTR.

Sample Programs

The best way to learn about a significant class library, such as the .NET Security Framework is to read and write many programs. This book provides many small programs that illustrate each of the pertinent features of .NET in isolation, which makes them easier to understand. The programs are clearly labeled in the text, and they can all be found in the software distribution that accompanies this book. These sample programs are provided in a self-extracting file on the book’s Web site. When expanded, a directory structure is created, whose default root is c:\OI\NetSecurity. The sample programs, which begin with the second chapter, are in directories Chap02, Chap03, and so on. All the samples for a given chapter are in individual folders within the chapter directories. The names of the folders are clearly identified in the text.

This book is part of The Integrated .NET Series. The sample programs for other books in the series are located in their own directories underneath \OI, so all the .NET examples from all books in the series will be located in a common area as you install them. These programs are furnished solely for instructional purposes and should not be embedded in any software product. The software (including instructions for use) is provided “as is” without warranty of any kind.

Web site

The Web site for the book series is:www.objectinnovations.com/dotnet.htm. A link is provided at that Web site for downloading the sample programs for this book.



Download the Index file related to this title.


Submit Errata

More Information

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020