Property IterationCount As Integer

int IterationCount {get; set;}

using (IPasswordDerivedBytes pd = DerivedBytes(TEST_PASSWORD))
{
    pd.IterationCount = 1000;
    byte[] sha1Hash = SHA1.Create().ComputeHash(Password.Encoding.GetBytes(TEST_PASSWORD));
    Rfc2898DeriveBytes pbytes = new Rfc2898DeriveBytes(sha1Hash, DefaultSalt.ToArray(), 1000);
    Assert.AreEqual(pd.GetBytes(20), pbytes.GetBytes(20));
    Assert.AreEqual(pd.GetBytes(35), pbytes.GetBytes(35));

    byte[] test1 = pd.GetBytes(40);
    byte[] test2 = pbytes.GetBytes(40);

    //'RFC' implementation resuses 5 bytes already generated with 'GetBytes(35)', if you call reset these behave the same
    Assert.AreNotEqual(test1, test2);

    Buffer.BlockCopy(test2, 5, test2, 0, 35); //strip the first five bytes
    Array.Resize(ref test1, 35);
    Array.Resize(ref test2, 35);

    Assert.AreEqual(test1, test2); //now they should be the same
}

Using pd As IPasswordDerivedBytes = DerivedBytes(TEST_PASSWORD)
    pd.IterationCount = 1000
    Dim sha1Hash As Byte() = SHA1.Create().ComputeHash(Password.Encoding.GetBytes(TEST_PASSWORD))
    Dim pbytes As New Rfc2898DeriveBytes(sha1Hash, DefaultSalt.ToArray(), 1000)
    Assert.AreEqual(pd.GetBytes(20), pbytes.GetBytes(20))
    Assert.AreEqual(pd.GetBytes(35), pbytes.GetBytes(35))

    Dim test1 As Byte() = pd.GetBytes(40)
    Dim test2 As Byte() = pbytes.GetBytes(40)

    ''RFC' implementation resuses 5 bytes already generated with 'GetBytes(35)', if you call reset these behave the same
    Assert.AreNotEqual(test1, test2)

    Buffer.BlockCopy(test2, 5, test2, 0, 35)
    'strip the first five bytes
    Array.Resize(test1, 35)
    Array.Resize(test2, 35)

        'now they should be the same
    Assert.AreEqual(test1, test2)
End Using