Systems and methods for controlling access to a mobile device. A method for unlocking a mobile device includes detecting a user input comprising two or more user actions performed at one or more physical input buttons of the mobile device when the mobile device is in a lock state. The lock state prevents use of at least one functionality of the mobile device. Each user action corresponds to a code. The method also includes determining whether the detected user input is valid, and changing a state of the mobile device from the lock state to an unlock state to enable the use of the at least one functionality of the mobile device if the detected user input is valid.