public override void SetIV(ReadOnlySpan <byte> iv)
{
var span = State.AsSpan();
var sigma = Sigma32.AsSpan();
sigma.CopyTo(span);
var keySpan = MemoryMarshal.Cast <byte, uint>(Key.Span);
keySpan.CopyTo(span.Slice(4));
var ivSpan = MemoryMarshal.Cast <byte, uint>(iv);
ivSpan.Slice(0, 4).CopyTo(span.Slice(12));
ChaChaRound(State);
span.Slice(12).CopyTo(span.Slice(8));
span.Slice(0, 4).CopyTo(span.Slice(4));
sigma.CopyTo(span);
State[14] = ivSpan[4];
State[15] = ivSpan[5];
}
public void SetIV(ReadOnlySpan <byte> iv)
{
var span = State.AsSpan();
var sigma = Sigma32.AsSpan();
sigma.CopyTo(span);
var keySpan = MemoryMarshal.Cast <byte, uint>(Key.Span);
keySpan.CopyTo(span[4..]);