Is it permissible to greet a non-mahram woman with "salam"?

Allah has commanded the spreading of peace (salam) and made it a means of fostering love among believers. This applies to all believers, however, there is a specific ruling concerning a man and a non-mahram woman. There is no harm in a man greeting an old woman with salam, but it is not appropriate for him to greet a young woman if there is a risk of fitnah (temptation). As for an old woman who does not pose a risk of fitnah, it is permissible for her to greet a man with salam and for him to return her greeting. However, a man should not greet a young non-mahram woman with salam, nor should she return his greeting if he greets her, nor should she initiate the greeting to him. If there is a group of women, a man may greet them with salam, or if there is a large group of men, and they greet a single woman, it is permissible, provided there is no fear of fitnah.