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Wyszukujesz frazę "phase encoding" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
A known-plaintext attack on iterative random phase encoding in fractional Fourier domains
Autorzy:
Yin, F.
He, Q.
Liu, Z.
Powiązania:
https://bibliotekanauki.pl/articles/174043.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image encryption
phase encoding
known-plaintext attack
Opis:
Known-plaintext attack is considered for decrypting the image generated by iterative random phase encoding in fractional Fourier transform domains. The double random phase encoding in Fourier domains is introduced to design the known-plaintext attack procedure. The decryption test is explored without both fractional order and these random phase masks. Some numerical simulations are made to demonstrate the validity of the known-plaintext attack.
Źródło:
Optica Applicata; 2017, 47, 1; 131-139
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-security image encryption by multiplexing phase encoding in domains of dual optical transforms
Autorzy:
Li, Zhihui
Gao, Bin
Pan, Xiaoou
Li, Linlin
Wang, Chenxuan
Zuo, Weizhuo
Ji, Yu
Liu, Shutian
Liu, Zhengjun
Powiązania:
https://bibliotekanauki.pl/articles/27310099.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
extended fractional Fourier transform
geometric operations
random phase encoding
Opis:
A novel optical image encryption is proposed based on multiplexing of the random phase encoding with shift and rotation operations in domains of two transforms, extended fractional Fourier transform (eFrFT) and Fresnel transform. The original image is subjected to eFrFT with the action of the random phase mask. The mask is shifted and rotated to enhance the security of this encryption method. The image obtained from eFrFT is entered into Fresnel diffraction by the use of the phase mask to obtain the final encrypted image. We plan for the phase keys to be multiplexed in order to decrease the amount of keys that need to be stored in an application. Here, the displacement, rotation angle, and wavelength in this system can be used as additional keys to improve the security and reliability of the encryption system. Numerical experiments are conducted to verify the effectiveness and security of the method. The findings demonstrate that the keys are sufficiently sensitive for high security.
Źródło:
Optica Applicata; 2023, 53, 3; 447--466
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressive-sensing-based double-image encryption algorithm combining double random phase encoding with Josephus traversing operation
Autorzy:
Jiang, Hao
Nie, Zhe
Zhou, Nanrun
Zhang, Wenquan
Powiązania:
https://bibliotekanauki.pl/articles/173461.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image encryption
compressive sensing
double random phase encoding
Josephus traversing
Opis:
A double-image encryption scheme based on compressive sensing is designed by combining a double random phase encoding technique with Josephus traversing operation. Two original images are first compressed and encrypted by compressive sensing in the discrete wavelet domain and then connected into a complex image according to the order of the alternate rows. Moreover, the resulting image is re-encrypted into stationary white noise by a double random phase encoding technique. Lastly, Josephus traversing method is utilized to scramble the transformed image. The initial states of the Henon chaotic map are the secret keys of this double-image encryption algorithm, which can be used to control the construction of the measurement matrix in compressive sensing and generation of the random-phase mask in double random phase encoding. Simulation results show that the proposed double-image encryption algorithm is effective and secure.
Źródło:
Optica Applicata; 2019, 49, 3; 445-459
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concealing information in security hologram using interferometry
Autorzy:
Sharma, Amit Kumar
Chauhan, Prashant
Varshney, Anshu D.
Powiązania:
https://bibliotekanauki.pl/articles/2172832.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hologram
security hologram
encoded hologram
information encoding
concealed phase
Opis:
A new method utilizing holographic interferometry technique is described to conceal information in security holograms for enhancing their anti-counterfeiting ability. This concealed information can only be imitated if security hologram is illuminated through correct decoding wavefront generated through a key hologram. In decoding process, three spatially separated focus spots emerge at predefined positions which upon divergence further generate interferometric fringes modulated with concealed information in them. When security hologram is perfectly aligned, interferometric fringes disappear and concealed information becomes visible. The advantage of encoding through this technique lies in the fact that relative repositioning of key and security hologram becomes much easier and also additionally brings multifold improvement in the security level of the verification systems.
Źródło:
Optica Applicata; 2022, 52, 3; 385--394
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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