Word Template in CEURART for One Column Amina Yahi 1 , Tewfik Bekkouche 2 , Mohamed El Hossine Daachi 3 and Nacira Diffellah 4 1,2,3,4 Mohamed El Bachir El Ibrahimi University, El-Anasser, Bordj Bou Arreridj, 34030, Algérie Abstract In this paper, an opto-digital encryption scheme based on a modified Double Random Phase Encoding (DRPE) system is proposed. Two biometric modalities are used in this work which is the face and the corresponding finger print of the same person. Firstly the face biometric image is encrypted chaotically using the permutation-diffusion architecture. Then obtained encrypted face is multiplied element by element by a constructed mask formed by injecting the finger print image within the phase of this mask. The obtained result will be transformed into a frequency domain by the two-dimensional Fourier transform or any of its derivatives, resulting complex image is exactly the encrypted biometric image. Experiment computer simulations confirm the efficiency of this work in terms of histogram analysis, loss data and sensitivity test when compared with existing works. Keywords 1 Biometric images, DRPE, Opto digital, Permutation-diffusion, Finger print, Chaotically, Fourier transform, histogram analysis 1. Introduction Today, in this era of information and communication technology, where we live more digitally than we believe, especially after the global quarantine because of the spread of coronavirus. As a result, unprecedented increase in the use of social media by sharing, sending and receiving of information, even for things that didn’t need the use of online connectivity, their digitalization was required, and not optional, as it was before. For example: videoconferences, ehealth, e-commerce, online education, online meeting and so on. Image plays an important role in the data transfer. Given the privacy and the confidentiality of most of them like military images, medical images etc... Thus, image security has become increasingly essential, and a key challenge to protect it from digital attacks such as thefts, espionage, modifications, denigration… To defeat the problem mentioned above, many researchers invested to develop several secure types of algorithms such as steganography [1,2], watermarking [3,4], and image encryption [5,6]. Since ancient times to today, Image Encryption is considered one of the most effective protection methods, which is defined as the method of transforming the whole image into an unrecognized one [7]. We distinguish two types of encryption domains, spatial domain which is based on changing the pixels positions of the plain image under the control of chaotic sequences [8] and changing their values by means of an XOR operator [9], these two steps named respectively diffusion and confusion. Regarding image encryption in the frequency domain, it’s performed using fast transform algorithms, such as fast Fourier transforms, Hadamard transforms, and Hartley transform [9]. The optical image encryption scheme is essentially based on the famous double random phase encoding (DRPE), by using the discrete Fourier transform (DFT) [9], presented for the first time by Refregier and Javidi [11]. It consists to use two random masks, one in the spatial plane and the other in the Fourier plane, in order to encrypt the primary image into stationary white noise [10, 11]. In order to give more effective results, DRPE has undergone many modifications, such as the use of parametric transforms [12, 13] instead of Proceedings ICCSA'2021, May 25–26, 2021, Oum El Bouaghi, Algeria EMAIL: amina.yahi994@gmail.com (A. Yahi); bekkou66@hotmail.com (T. Bekkouche); mohamed.daachi@univ-bba.dz (M. E. H. Daachi) ©฀ 2021 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0). CEUR Workshop Proceedings (CEUR-WS.org)