Rfc2898DeriveBytes.GetBytes Method

Returns the pseudo-random key for this object.

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

public override byte[] GetBytes(
	int cb
)

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
{
    Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1, myIterations);
    Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);
    // Encrypt the data.
    TripleDES encAlg = TripleDES.Create();
    encAlg.Key = k1.GetBytes(16);
    MemoryStream encryptionStream = new MemoryStream();
    CryptoStream encrypt = new CryptoStream(encryptionStream, encAlg.CreateEncryptor(), CryptoStreamMode.Write);
    byte[] utfD1 = new System.Text.UTF8Encoding(false).GetBytes(data1);


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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