The following is a system in which a person may use a Cellular (Mobile) Telephone, a PDA or any other handheld computer to make a purchase. This is an example only. The process may entail any type of transaction which requires authentication, such as any financial transaction, any access control (to account information, etc.), and any physical access scenario such as doubling for a passport or an access key to a restricted area (office, vault, etc.). It may also be used to conduct remote transactions such as those conducted on the Internet (E-Commerce, account access, etc.). In the process, a multi-factor authentication is used.