private byte[] encodeString(byte[] str)
{
if (str == null || str.Length == 0)
{
return(XofUtilities.LeftEncode(0));
}
return(Arrays.Concatenate(XofUtilities.LeftEncode(str.Length * 8L), str));
}
/// <summary>
/// Base constructor
/// </summary>
/// <param name="bitLength">bit length of the underlying SHAKE function, 128 or 256.</param>
/// <param name="N">the function name string, note this is reserved for use by NIST. Avoid using it if not required.</param>
/// <param name="S">the customization string - available for local use.</param>
public CShakeDigest(int bitLength, byte[] N, byte[] S) : base(bitLength)
{
if ((N == null || N.Length == 0) && (S == null || S.Length == 0))
{
diff = null;
}
else
{
diff = Arrays.ConcatenateAll(XofUtilities.LeftEncode(rate / 8), encodeString(N), encodeString(S));
DiffPadAndAbsorb();
}
}