A method and system for protection of and secure access to a computer system or computer network from a portable device. The method includes the steps of receiving a first login account identifier, such as a user name from a user in communication with the computer system or network. A determination is made if the user is recognized and enrolled from the first login account identifier. If the user is recognized, a series of randomly generated visual images is displayed including one visual image from an image category which has been pre-selected by the user upon enrollment. An image category identifier is randomly assigned to each visual image in the series. An image category identifier is entered and received. If the login account identifier and the image category are validated, access is permitted to the computer system or network from the portable device.