Assalaamu alaykum. I give charity secretly. Partly because secret optional acts are better. Another reason is that if my parents come to know about my charity, I fear they will not let me give charity at all, especially my father. A few days ago, I helped one of my relatives by lending him some money. The situation was very urgent for him. My father found out about it. Today, he commanded me that before helping anybody else (hence giving in charity), I ask his permission. I do not like it, because I know my father. Unfortunately he is a bit stingy about giving charity. If I ask him in the future, he will not let me give any charity at all. Also, as giving in charity is an optional act (but I love to give it), will it become obligatory upon me to give it once I ask my father?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger. 

If you give charity from your own money, then you do not have to ask your father's permission, and your father has no right to prevent you from giving charity. This is not obligatory dutifulness towards him as a parent, as there is no harm that affects him due to you giving charity with some of your money.

However, if it is your father who gave you this money to spend it in any given field, then you have to seek his permission before disposing of it if you wish to spend it in any field other than that for which he gave you the money, because it is obligatory to take the intent of the donor into consideration.

In any case, you have to be dutiful to your father in what is permissible.

As for giving charity from your own money, then you should hide this from him so that you would not make him angry.

Allah knows best.