A system for printing a security identification on a print medium is disclosed. The system comprises a mobile telecommunications device. The mobile telecommunications device in turn comprises a sensor module for sensing data encoded on a surface of a print medium, the data encoding at least a print media identifier of the print medium. The mobile telecommunications device further comprises means for determining the print media identifier from the data and for retrieving a security identification associated with the print media identifier from a storage medium. A printer module of the mobile telecommunications device then prints the security identification on the print medium.