Cryptography and Data Access 

The classes in the .NET Framework System.Security.Cryptography namespace can be used from your ADO.NET applications to ensure that data cannot be read or modified by unauthorized third parties. Some classes are wrappers for the unmanaged Microsoft CryptoAPI, while others are managed implementations.

Working with Cryptography

Cryptography Overview in the Cryptographic Services node provides an overview for understanding key concepts, and .NET Framework Cryptography Model explains its implementation in the .NET Framework and provides links to additional topics. Cryptographic Tasks provides links to topics describing how to encrypt and decrypt data, work with hash codes, generate cryptographic signatures and other cryptographic topics.

Using Hash Codes for Data Integrity

Unlike cryptography, which allows data to be encrypted and then decrypted, hashing data is a one-way process. Hashing data is useful when you want to prevent tampering by checking that data has not been altered: given identical input strings, hashing algorithms always produce identical short output values that can easily be compared. Ensuring Data Integrity with Hash Codes describes how you can generate and verify hash values.

Using Protected Configuration to Encrypt .config Files

Encrypting Configuration Information Using Protected Configuration demonstrates how you can encrypt sensitive information in configuration files, such as the Web.config file in an ASP.NET application or the App.config file for a Windows application. See Encrypting Configuration Information Using Protected Configuration, Encrypting and Decrypting Configuration Sections, and Walkthrough: Encrypting Configuration Information Using Protected Configuration.

Encryption in SQL Server 2005

SQL Server 2005 offers functions that encrypt sensitive information by converting clear text to cipher text. Column-level and cell-based encryptions are also supported by new Transact-SQL statements. See "Security Considerations for SQL Server" in SQL Server Books Online, and subordinate topics such as "Encryption Hierarchy," which discusses encryption mechanisms in SQL Server 2005.

See Also