This is a very funny question. Bitcoin cannot be a HALAL because this word can only be applied to muslim cuisine. When we say HALAL it refers to a special way of preparing meat as prescribed by Muslim law. If bitcoin is a kind of meat then it could be prepared in a way so it can be called HALAL but this is cryptocurrency that we are talking thus bitcoin cannot be HALAL but muslims can use bitcoin without worries and without violating any Islamic Laws.