Cryptography Application Block

 
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Cryptography Application Block

patterns & practices Developer Center

Enterprise Library for .NET Framework 1.1

patterns & practices Developer Center

Microsoft Corporation

June 2005

Summary

This page provides an overview of the Enterprise Library Cryptography Application Block. This is reusable and extensible source code-based guidance that simplifies development of common cryptographic functionality in .NET-based applications.

* Important Note: The January 2005 release of Enterprise Library is no longer available to download, due to important issues discovered after the release. Customers building new applications should move to the June 2005 release. Customers who have already adopted the January release must apply the patches available on Enterprise Library Community site. Please direct any questions to the community site or to devfdbck@microsoft.com

Contents

Introduction to the Cryptography Application Block
Design of the Cryptography Application Block
Test Drive
Feedback and Support
June 2005 Release Updates
Roadmap
Authors and Contributors
Related Titles

Introduction to the Cryptography Application Block

The Microsoft Enterprise Library Cryptography Application Block simplifies how developers incorporate cryptography functionality in their applications. Applications can use the application block for a variety of tasks, such as encrypting information, creating a hash from data, and comparing hash values to verify that data has not been altered.

The Cryptography Application Block has the following features:

  • It reduces the requirement to write boilerplate code to perform standard tasks, providing implementations that you can use to solve common application cryptography problems.
  • It helps maintain consistent cryptography practices, both in an application and across the enterprise.
  • It eases the learning curve for developers by using a consistent architectural model across the various areas of functionality that are provided.
  • It provides implementations that you can use to solve common application cryptography problems.
  • It is extensible; supporting additional implementations of cryptography providers.

Common Scenarios

Developers frequently write applications that require encryption and hashing capabilities to meet the security requirements of their organization. Data that is created and maintained by applications, as well as configuration information, often needs to be encrypted. Additionally, passwords that are used to access application functionality or data need to be hashed.

The Cryptography Application Block simplifies the work of developers by abstracting application code from specific cryptography providers. You can change underlying providers through configuration changes without changing the underlying application code. It also encapsulates best-practice implementation of common challenges associated with cryptography such as encrypting and persisting cryptographic keys.

Audience Requirements

This guide is intended for software architects and software developers. To benefit fully from this guide, you should have an understanding of the following technologies:

  • Microsoft Visual C# development tool or Microsoft Visual Basic development system
  • .NET Framework (including .NET Framework cryptography concepts)

Highlights of the Enterprise Library Cryptography Application Block

The Enterprise Library Cryptography Application Block includes the following new features:

  • A graphical tool for managing configuration settings
  • Two implementations of a hash provider
  • A small number of methods that simplify the most common cryptography tasks

System Requirements

The requirements for the Cryptography Application Block are the following:

  • Microsoft Windows 2000, Windows XP Professional, or Windows Server 2003 operating system
  • Microsoft .NET Framework version 1.1
  • Microsoft Visual Studio .NET 2003

Cryptography Application Block Dependencies

The application blocks that are provided with the Enterprise Library are designed to be used in conjunction with each other. Sometimes, the application blocks have dependencies on other application blocks and code that is included with the Enterprise Library. The Cryptography Application Block has the following dependencies:

  • The Configuration Application Block. The Cryptography Application Block uses the Configuration Application Block to read its configuration information, and to ensure that the keys that are used for encryption are themselves encrypted.
  • Common library functionality, such as instrumentation. It provides various functions for exposing events and data used for system management. It also provides classes that help with the correct use of DPAPI.

In addition, the application block uses XML files to store configuration information. The recommended way to modify this information is to use the Enterprise Library Configuration Console.

Design of the Cryptography Application Block

The Cryptography Application Block was designed to achieve the following goals:

  • Provide a simple and intuitive interface to the commonly required functionality
  • Encapsulate the logic that is used to perform the most common application cryptography tasks
  • Present a standard consistent model for common cryptography tasks
  • Make sure that the application block is extensible
  • Make sure minimal or negligible performance impact compared to manually written cryptography code that accomplishes the same functionality

Figure 1 illustrates the design of the Cryptography Application Block.

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Figure 1. Design of the Cryptography Application Block

The Cryptography Application Block is designed to externalize all decisions about how to deal with cryptography from a running application. This design lets you change cryptography behavior without changing the code of the application.

Test Drive

The Cryptography Application Block has been developed as a result of analyzing common enterprise development challenges and successful solutions to these challenges. However, because each application is unique, you will not find this application block suitable for every application. To evaluate this application block and determine its applicability to your projects, Microsoft suggests you dedicate at least half of a day to explore the application block. The following is a suggested evaluation approach:

  1. Download Enterprise Library.
  2. Install Enterprise Library and compile all application blocks and tools.
  3. Read the "Introduction" and "Scenarios and Goals" sections of the documentation.
  4. Compile and run the QuickStart samples, and read through the related "QuickStart Walkthroughs" and "Key Scenarios" sections of the documentation.
  5. If the application block looks like a good fit for your application, try implementing a simple use case in your application or in a throw-away prototype application using the application block.

Feedback and Support

Questions? Comments? Suggestions? To provide feedback about this application block, or to get help with any problems, please visit the Enterprise Library Community site. The community site is the preferred feedback and support channel because it allows you to share your ideas, questions, and solutions with the entire community. Alternatively, you can send e-mail directly to the Microsoft patterns & practices team at devfdbck@microsoft.com, although we are unable to respond to every message.

Enterprise Library is a guidance offering, designed to be reused, customized, and extended. It is not a Microsoft product. Code-based guidance is shipped "as is" and without warranties. Customers can obtain support through Microsoft Support Services for a fee, but the code is considered user-written by Microsoft support staff. For more information about our support policy, see the Enterprise Library home page

June 2005 Release Updates

The June 2005 release of Enterprise Library is a minor update of the original version released in January 2005. Please see About the June 2005 Release for more information on the updates to the application blocks for the June 2005 release.

Roadmap

An updated release of the Cryptography Application Block is planned for the next release of Enterprise Library. This release will target the .NET Framework 2.0 and Visual Studio 2005 and will include additional improvements based on customer feedback.

Authors and Contributors

The Enterprise Library Cryptography Application Block was produced by the following people:

  • Program Managers: William Loeffler (Microsoft Corporation), Linh Nguyen (Avanade Inc)
  • Product Manager: Tom Hollander (Microsoft Corporation)
  • Architects: Edward Jezierski (Microsoft Corporation), Kyle Huntley (Avanade Inc)
  • Development: Scott Densmore, Peter Provost (Microsoft Corporation), Brian Button (Murphy and Associates), Timothy Shakarian (Avanade Inc)
  • Test: Mohammad Al-Sabt, Carlos Farre (Microsoft Corporation), Mani Krishnaswami, Gokulaprakash Thilagar, Rohit Sharma, Prashant Bansode, Jeevarani Radhakrishnan, Dhananjaya Rao (Infosys Technologies Ltd), Pavan Kumar Sura (Volt)
  • Documentation and Samples: RoAnn Corbisier (Microsoft Corporation), Tim Osborn (Ascentium Corporation), Roberta Leibovitz (Modeled Computation LLC), Paul Slater (Wadeware LLC), Tina Burden McGrayne (Linda Werner & Associates Inc)

Many thanks to the following advisors who provided invaluable assistance:

  • Rudy Araujo, Yen-Ming Chen, Mark Curphey and David Raphael of Foundstone Inc.
  • Benoit Morneau and Shoichi Takasaki of Bowne Global Solutions

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patterns & practices Developer Center

Retired Content

This content is outdated and is no longer being maintained. It is provided as a courtesy for individuals who are still using these technologies. This page may contain URLs that were valid when originally published, but now link to sites or pages that no longer exist.

The latest Enterprise Library information can be found at the Enterprise Library site.
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