Optical Encryption and Decryption

X.-C. Yuan, Shaohua Tao, Wai C. Cheong +4 more

A hybrid encryption and decryption technique for optical information security is proposed. In this method, the iterative Fourier transform algorithm is employed to optimize the encrypted hologram and the decryption key as binary phase-only diffractive optical elements, which were fabricated by electron-beam lithography. In a simple optical setup, the optical decryption is implemented by superimposing the encrypted hologram and the decryption key. Numerical simulation and optical experiment confirm the proposed technique as a simple and easy implementation for optical decryption.

吴克难 Wu Kenan, 胡家升 Hu Jiasheng, 乌旭 Wu Xu

Hongtao Wang, Haoran Zhang, Xiaoyan Zhou +8 more

Ting‐Chung Poon, Tae-Geun Kim, Kyu B. Doh

We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea.

Lilin Yi, T Zhang, Z X Li +3 more

We propose to all-optically encrypt and decrypt high-speed optical signals using the stimulated Brillouin scattering (SBS) effect in optical fiber for the first time. The spectral-shaped SBS gain or loss distorts the broadband optical signal so as to realize optical encryption. A corresponding SBS loss or gain with the same spectral shape and amplitude recovers the distorted signal to implement optical decryption. We experimentally demonstrate the SBS encryption/decryption process on 10.86 Gb s −1 non-return-to-zero-on-off-keying (NRZ-OOK) data using phase-modulated Brillouin pumps to generate a spectral-shaped SBS gain/loss encryption key, and no power penalty is observed for the best decryption case. The proposed all-optical encryption/decryption method is completely compatible with existing fiber-optic communication systems.

侯俊峰 Hou Junfeng, 黄素娟 HUANG Su-juan, Guohai Situ