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Rfc2898DeriveBytes.Rfc2898DeriveBytes(String, Int32, Int32) Constructor

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

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

public:
Rfc2898DeriveBytes (
	String^ password, 
	int saltSize, 
	int iterations
)
public Rfc2898DeriveBytes (
	String password, 
	int saltSize, 
	int iterations
)
public function Rfc2898DeriveBytes (
	password : String, 
	saltSize : int, 
	iterations : int
)
Not applicable.

Parameters

password

The password used to derive the key.

saltSize

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

iterations

The number of iterations for the operation.

Exception typeCondition

ArgumentException

The specified salt size is smaller than 8 bytes or the iteration count is less than 1.

ArgumentNullException

The password or salt is a null reference (Nothing in Visual Basic).

ArgumentOutOfRangeException

iterations is out of range. This parameter requires a non-negative number.

The salt size must be 8 bytes or larger and the iteration count must be greater than zero. The minimum recommended number of iterations is 1000.

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 on PBKDF2, see RFC 2898,"PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site at http://www.rfc-editor.org. 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 using the MSIL Disassembler (Ildasm.exe) l, a hex editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

The following code example uses the Rfc2898DeriveBytes class to create two identical keys for the TripleDES class. It then encrypts and decrypts some data using the keys.

Rfc2898DeriveBytes ^ k1 = gcnew Rfc2898DeriveBytes( pwd1,salt1,myIterations );
Rfc2898DeriveBytes ^ k2 = gcnew Rfc2898DeriveBytes( pwd1,salt1 );

Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1,
    myIterations);
Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);

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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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