Erro Blowfish Descriptografia

function TBlowFishCripto.Decrypt(const encrypted: string;
  out decrypted: string): boolean;
var
  de: TBlowFishDeCryptStream;
  stream: TStringStream;
begin
  if length(encrypted) = 0 then
  begin
    Result := True;
    decrypted := '';
    Exit;
  end;
  try
    stream := TStringStream.Create(encrypted);
    de := TBlowFishDeCryptStream.Create(FKey, stream);
    decrypted := de.ReadAnsiString; { <-- AQUI O ERRO 203 acontece }
    Result := True;
  finally
    FreeAndNil(de);
    FreeAndNil(stream);
  end;
end;