A portable electronic device comprising: a touch-sensitive display comprising a display , a memory and a plurality of display touch-sensors arranged and constructed to detect touches on the touch-sensitive display ; a keyboard comprising: a plurality of mechanical keys associated with a plurality of characters, the mechanical keys including depressible keycaps to output respective characters of the plurality of characters; a plurality of keyboard touch sensors arranged and constructed to detect touches on the mechanical keys ; a processor coupled to the keyboard and to the touch-sensitive display and operable to: detect a touch at a location associated with a signature entry field displayed on the touch-sensitive display ; in response to detecting the touch at the location associated with the signature entry field , enter a keyboard signature process; detect a moving touch on the mechanical keys of the keyboard , along a path of contact of the touch on the mechanical keys of the keyboard when in the keyboard signature process, wherein the path of contact of the touch is determined by identifying coordinate locations of contact with each of the mechanical keys along the path of the moving touch; store the coordinate locations temporarily in the memory; and in response to detecting completion of the moving touch, enter a signature defined by the path of contact of the touch on the mechanical keys into the signature entry field . a touch-sensitive display comprising a display , a memory and a plurality of display touch-sensors arranged and constructed to detect touches on the touch-sensitive display ; a keyboard comprising: a plurality of mechanical keys associated with a plurality of characters, the mechanical keys including depressible keycaps to output respective characters of the plurality of characters; a plurality of keyboard touch sensors arranged and constructed to detect touches on the mechanical keys ; a plurality of mechanical keys associated with a plurality of characters, the mechanical keys including depressible keycaps to output respective characters of the plurality of characters; a plurality of keyboard touch sensors arranged and constructed to detect touches on the mechanical keys ; a processor coupled to the keyboard and to the touch-sensitive display and operable to: detect a touch at a location associated with a signature entry field displayed on the touch-sensitive display ; in response to detecting the touch at the location associated with the signature entry field , enter a keyboard signature process; detect a moving touch on the mechanical keys of the keyboard , along a path of contact of the touch on the mechanical keys of the keyboard when in the keyboard signature process, wherein the path of contact of the touch is determined by identifying coordinate locations of contact with each of the mechanical keys along the path of the moving touch; store the coordinate locations temporarily in the memory; and in response to detecting completion of the moving touch, enter a signature defined by the path of contact of the touch on the mechanical keys into the signature entry field . detect a touch at a location associated with a signature entry field displayed on the touch-sensitive display ; in response to detecting the touch at the location associated with the signature entry field , enter a keyboard signature process; detect a moving touch on the mechanical keys of the keyboard , along a path of contact of the touch on the mechanical keys of the keyboard when in the keyboard signature process, wherein the path of contact of the touch is determined by identifying coordinate locations of contact with each of the mechanical keys along the path of the moving touch; store the coordinate locations temporarily in the memory; and in response to detecting completion of the moving touch, enter a signature defined by the path of contact of the touch on the mechanical keys into the signature entry field . <EOS>