What is the ruling on someone who works to ensure the quality of various computer programs for mobile phones, some of which are used for voting in competitions such as (Arab Idol), some of which display ringtones that may be Islamic anasheeds or forbidden songs, or for subscribing to services that may be permissible or impermissible, and what is the ruling on ensuring the quality of programs for booking airline tickets and hotels that use payment cards?

Programs are divided into two categories: The first is what is used only for unlawful matters. This type is forbidden, and it is impermissible to create or assist in its creation. Similar to this is what is predominantly used for unlawful purposes.

The second category is what can be used for both lawful and unlawful matters equally. The basic ruling for this is permissibility, unless it is known or strongly suspected that it will be used for unlawful purposes. Thus, anything that is used in an unlawful manner, or is predominantly suspected of being so used, is forbidden to manufacture and sell.