Methods and systems receive an electronic scanned image generated by activity of an application running on a portable computerized device, and calculate a cryptographic digest from data of the electronic scanned image using a second computerized device. Also, such methods and systems encrypt the cryptographic digest using an encryption key stored on the portable computerized device to create a content signature of the cryptographic digest, and send the content signature to the second computerized device. The authenticity of a copy of the electronic scanned image provided by the second computerized device is verified by recalculating the content signature (based on the copy of the electronic scanned image) using the encryption key from the portable device.