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Rfc2898DeriveBytes Constructor (String, Int32)

Updated: December 2008

Initializes a new instance of the Rfc2898DeriveBytes class using the password and salt size to derive the key.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

	String^ password, 
	int saltSize


Type: System::String

The password used to derive the key.

Type: System::Int32

The size of the random salt that you want the class to generate.


The specified salt size is smaller than 8 bytes.


The password or salt is nullptr.

The salt size must be 8 bytes or larger.

RFC 2898 includes methods for creating a key and initialization vector (IV) from a password and salt. You can use PBKDF2, a password-based key derivation function, to derive keys using a pseudo-random function that allows keys of virtually unlimited length to be generated. The Rfc2898DeriveBytes class can be used to produce a derived key from a base key and other parameters. In a password-based key derivation function, the base key is a password and the other parameters are a salt value and an iteration count.

For more information about PBKDF2, see RFC 2898, "PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site. See section 5.2, "PBKDF2," for complete details.

Security noteSecurity Note:

Never hard-code a password within your source code. Hard-coded passwords can be retrieved from an assembly by using the MSIL Disassembler (Ildasm.exe), by using a hexadecimal editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0




December 2008

Removed incorrect sample.

Customer feedback.