Patent attributes
A digital device including a camera unit; and a controller configured to in response to a request to execute a first application on the digital device having a first security authentication level, control the camera unit to capture first vein image data at a first depth of a particular body part of a target and perform a first authentication process by comparing the captured first vein image data with prestored first vein image data, and in response to a request to execute a second application on the digital device having a second security authentication level more secure than the first authentication level, control the camera unit to capture second vein image data at a second depth of the particular body part of the target and perform the first authentication process and a second authentication process by comparing the captured second vein image data with prestored second vein image data.