class Test
{
  string GetSha256(string INPUT, Encoding encoding = null)
  {
    if (encoding == null) encoding = new UTF8Encoding(false);
    var sha = System.Security.Cryptography.SHA256.Create();
    byte[] inputBytes = Encoding.UTF8.GetBytes(INPUT);
    byte[] hash = sha.ComputeHash(inputBytes);
    string sha256 = string.Empty;
    for (int i = 0; i < hash.Length; i++)
        sha256 += hash[i].ToString("X2");
    return sha256;
  }
}