Secure optodigital protocol to manage messages using the multiplexing of processed QR codes

SORAYDA TREJOS; JOHN FREDY BARRERA; ROBERTO TORROBA

León

Conferencia; Speckle 2015 Conference; 2015

Centro de Investigaciones en Óptica

In this work a protocol for the safe and efficient handling of messages is presented. The protocol is implemented using a digital holographic technique and a 2f optical processor with a ground glass diffuser placed in its input plane. Several QR codes representing letters of the alphabet are optically processed and holographically stored. The holograms of the optically processed QR codes are filtered, positioned and finally multiplexed to obtain a single package containing all information. This package is multiplied by a random phase mask which gives security to the processed information. An authorized user receives the protected package and the complex conjugate of the random phase mask to recover the package. The QR codes are retrieved after applying a Fourier transform operation over the package. The codes are retrieved in the same plane without any kind of overlapping and with the natural speckle noise due to the optodigital processing. In order to recover the protected message, the user receives the right sequence of QR reading. Due to the properties of the QR scanning, all letters containing the message are completely free of any kind of noise or degradation. This protocol is suitable for multi-user environment, because many users can receive the same package and the same complex conjugate of the random phase mask but each user receives a different sequence to recover a particular message. Experimental results demonstrate the validity of the proposal.