Rfc2898DeriveBytes.GetBytes(Int32) Method
Definition
Important
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Returns the pseudo-random key for this object.
public:
override cli::array <System::Byte> ^ GetBytes(int cb);public override byte[] GetBytes (int cb);override this.GetBytes : int -> byte[]Public Overrides Function GetBytes (cb As Integer) As Byte()Parameters
- cb
- Int32
The number of pseudo-random key bytes to generate.
Returns
A byte array filled with pseudo-random key bytes.
Exceptions
cb is out of range. This parameter requires a non-negative number.
Examples
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 = gcnew Rfc2898DeriveBytes( pwd1,salt1,myIterations );
Rfc2898DeriveBytes ^ k2 = gcnew Rfc2898DeriveBytes( pwd1,salt1 );
// Encrypt the data.
Aes^ encAlg = Aes::Create();
encAlg->Key = k1->GetBytes( 16 );
MemoryStream^ encryptionStream = gcnew MemoryStream;
CryptoStream^ encrypt = gcnew CryptoStream( encryptionStream,encAlg->CreateEncryptor(),CryptoStreamMode::Write );
array<Byte>^utfD1 = (gcnew System::Text::UTF8Encoding( false ))->GetBytes( data1 );
try
{
Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1,
myIterations);
Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);
// Encrypt the data.
Aes encAlg = Aes.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);
Try
Dim k1 As New Rfc2898DeriveBytes(pwd1, salt1, myIterations)
Dim k2 As New Rfc2898DeriveBytes(pwd1, salt1)
' Encrypt the data.
Dim encAlg As Aes = Aes.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)
Remarks
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.
