public void HChaCha20StateTestVector()
{
// https://tools.ietf.org/html/draft-irtf-cfrg-xchacha-03#section-2.2.1
// Arrange
var key = CryptoBytes.FromHexString("00:01:02:03:04:05:06:07:08:09:0a:0b:0c:0d:0e:0f:10:11:12:13:14:15:16:17:18:19:1a:1b:1c:1d:1e:1f".Replace(":", string.Empty));
var nonce = CryptoBytes.FromHexString("00:00:00:09:00:00:00:4a:00:00:00:00:31:41:59:27".Replace(":", string.Empty));
var cipher = new XChaCha20(key, 0);
// Act
var initialState = new uint[16];
cipher.HChaCha20InitialState(initialState, nonce);
// Assert
var expectedInitialState = new uint[]
{
0x61707865, 0x3320646e, 0x79622d32, 0x6b206574,
0x03020100, 0x07060504, 0x0b0a0908, 0x0f0e0d0c,
0x13121110, 0x17161514, 0x1b1a1918, 0x1f1e1d1c,
0x09000000, 0x4a000000, 0x00000000, 0x27594131
};
initialState.Should().BeEquivalentTo(expectedInitialState);
}