In this reported work, differential detection to eavesdrop the encoded information in the temporal phase coding code-shift-keying OCDMA system, is proposed and experimentally demonstrated. Differential detection can be used to distinguish the discrepancy in the two encoded signals.
We experimentally demonstrate the security vulnerability in the temporal phase coding single-user differential phase-shift keying (DPSK) and code-shift keying (CSK) OCDMA systems with a DPSK demodulator. In the experiment, we build up the 2.5Gbit/s DPSK- and CSK-OCDMA systems. In the systems, we use two 31-chip 640 Gchip/s superstructured fiber Bragg grating encoders for the signal encoding. In the receiving side, we remove the decoders and utilize the DPSK demodulator to detect the encoded signals directly. We successfully achieve the error-free BER performance and obtaine the clear open eye diagrams using the detection without the proper decoding. It indicates the existence of the eavesdropping vulnerability in the both systems. Furthermore, we also discuss the principle of DPSK demodulation attack.
We experimentally demonstrate the security vulnerability in the temporal phase coding single-user differential phase-shift keying (DPSK) and code-shift keying (CSK) OCDMA systems with a DPSK demodulator. In the experiment, we build up the 2.5Gbit/s DPSK- and CSK-OCDMA systems. In the systems, we use two 31-chip 640 Gchip/s superstructured fiber Bragg grating encoders for the signal encoding. In the receiving side, we remove the decoders and utilize the DPSK demodulator to detect the encoded signals directly. We successfully achieve the error-free BER performance and obtaine the clear open eye diagrams using the detection without the proper decoding. It indicates the existence of the eavesdropping vulnerability in the both systems. Furthermore, we also discuss the principle of DPSK demodulation attack.
In this paper, two vulnerabilities that allow an eavesdropper to extract data from an isolated user in a two-code-keying spectrally phase-coded optical-code-division-multiple-access (O-CDMA) system are experimentally demonstrated. One of these vulnerabilities stems from spectral dips that result from phase-to-amplitude conversion in the encoding process, which allows eavesdropping by using a narrowband tunable optical filter and a simple energy detector. A modified O-CDMA transmitter scheme that masks this vulnerability is demonstrated. A second, especially serious, vulnerability allows eavesdropping by using a differential-phase-shift-keying receiver. Both of these vulnerabilities arise from a structure in the coding and signaling schemes that allow an eavesdropper to recover data, with relatively simple hardware and without attempting to learn the codes
A novel technique to enhance the security of an optical code division multipleaccess (OCDMA) system against eavesdropping is proposed. It has been observed that whena single user is active in the network, an eavesdropper can easily sift the data beingtransmitted without decoding. To increase the security, a virtual user scheme is proposed andsimulated on a differential phase shift keying (DPSK) OCDMA system. By using the virtualuser scheme, the security of the DPSK-OCDMA system can be effectively improved and themultiple access interference, which is generally considered to be a limitation of the OCDMAsystem, is used to increase the confidentiality of the system.