Methods for authorizing actions using mobile phones. Embodiments include receiving from a person having authority to authorize the action, an identification of a phone number for obtaining authorization for the action, receiving from a person seeking the action a request for authorization of the action, sending an automated first message through a mobile phone network to the mobile phone, including a description of the action for which authorization is requested, and receiving, from the first mobile phone, a second message, which authorizes the action. Actions that are authorized, in different embodiments, include computer access, physical access, and financial transactions. In various embodiments, the phone number may be received through the mobile phone network through the Internet, through a local signal, or directly from the user.