TIdHMACSHA256.TIdHMACSHA384.TIdHMACSHA512 do not work in Delphi

Question

Why HashValue function of TIdHMACSHA256+ (Indy/delphi) always return empty? For example, the code below does not work.

var
  Hash: TIdHMACSHA256 ;
  HashValue: TBytes;
begin
  SetCurrentDir(ExtractFilePath(ParamStr(0)));
  Hash := TIdHMACSHA256 .Create;
  try
    Hash.Key := TEncoding.ASCII.GetBytes('devaee2');
    HashValue := Hash.HashValue(TFile.ReadAllBytes('menu.xml'));
    // HashValue is an empty array, why?
    Tag := Length(HashValue);
    TFile.WriteAllBytes('menu.xml.hash', HashValue);

  finally
    FreeAndNil(Hash);
  end;
end;

Answer 1

The problem is that you have not successfully loaded the OpenSSL libraries that are needed to implement the hash. Call IdSSLOpenSSL.LoadOpenSSLLibrary. You'll also need to make sure that your program can find suitable OpenSSL DLLs.