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Rfc2898DeriveBytes.GetBytes Method

Returns the pseudo-random key for this object.

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

'Declaration
Public Overrides Function GetBytes ( _
	cb As Integer _
) As Byte()

Parameters

cb
Type: System.Int32

The number of pseudo-random key bytes to generate.

Return Value

Type: System.Byte()
A byte array filled with pseudo-random key bytes.

ExceptionCondition
ArgumentOutOfRangeException

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

The Rfc2898DeriveBytes class implements PBKDF2 functionality by using a pseudorandom number generator based on HMACSHA1. The Rfc2898DeriveBytes class takes a password, a salt, and an iteration count, and then generates keys through calls to the GetBytes method. Repeated calls to this method will not generate the same key; instead, appending two calls of the GetBytes method with a cb parameter value of 20 is the equivalent of calling the GetBytes method once with a cb parameter value of 40.

The following example shows how to use the GetBytes method to get the key for an instance of Rfc2898DeriveBytes. This code example is part of a larger example provided for the Rfc2898DeriveBytes class.

Try 
    Dim k1 As New Rfc2898DeriveBytes(pwd1, salt1, myIterations)
    Dim k2 As New Rfc2898DeriveBytes(pwd1, salt1)
    ' Encrypt the data. 
    Dim encAlg As TripleDES = TripleDES.Create()
    encAlg.Key = k1.GetBytes(16)
    Dim encryptionStream As New MemoryStream()
    Dim encrypt As New CryptoStream(encryptionStream, encAlg.CreateEncryptor(), CryptoStreamMode.Write)
    Dim utfD1 As Byte() = New System.Text.UTF8Encoding(False).GetBytes(data1)

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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