In commercial relations, which are usually subject to international laws of trade and agreements made between them, banks play a very crucial role. Banks, as trusted agents by two businessmen in two countries, always seek to facilitate the transfer of money and also to guarantee the delivery of the goods to the importer and guarantee the receiving of the money by the exporter. This is usually done by different banking protocols and their currency credentials. Recently, due to numerous problems caused by sanctions in the international relations of Iranian banks, the transfer of currency to Iran will be practically associated with a very difficult and frustrating path. But, in spite of all the conditions, banks are always doing their best to provide the exporter with the resulting currency.