Robust Key Update with Controllable Accuracy Using Support Vector Machine for Secure OFDMA-PON

In this article, we first propose a novel secret key update scheme only with a single support vector machine (SVM). To achieve robust and efficient key management for secure orthogonal frequency division multiple access-based passive optical network (OFDMA-PON). The key sequences required to be shared between multiple optical network units (ONUs) and optical line terminal (OLT) are converted into partial quadrature amplitude modulation (QAM) symbol phases, and then masked into the whole upstream signal using two-dimensional chaos. The session keys can be distributed in real-time without consuming exclusive secure channels and resulting in data rate loss. A well-trained support vector machine (SVM) implemented at the receiver enables error-free key decision. Moreover, the numerous cross validations are conducted to verify the superior generalization performance under various parameters including key length and modulation format. The 16-QAM, 32-QAM, and 64-QAM OFDM signal transmissions are successfully demonstrated over 25 km standard single mode fiber (SSMF) by an experiment. The results show that the controllable restored accuracy of key can be realized by regulating the pivotal algorithm parameter to flexibly adapt to different system conditions, thus this scheme can be a promising efficient key update technology for future secure PON.