The off-line digital signal processing has been utilized by orthogonal frequency division multiplexing (OFDM) optical transmission security for evaluating and transmitting the security performance but, real-time secure optical OFDM (OOFDM) transmission is vital. Using FPGA boards for real-time encoding, we propose real-time safe optical OFDM transmission with chaotic data encoding for manifesting high-speed data transmission with strong physical layer security. Decode optical OFDM signals using pipelined digital-to-analog and analog-to-digital converters. In order to dynamically and flexibly map user data, we suggest a unique dynamic square amplitude modulation (QAM) approach that takes use of clutter. Chaotic systems, like randomization, have several benefits and are far more secure than conventional encryption techniques, like RSA (AES, DES). This prompted the creation of an effective technique for sending secure pictures across AWGN channels. In this study, a detailed description of the OOFDM-oriented bidirectional coding and scrambling approach is provided. The scattered light OFDM system is encrypted using public and private keys in the suggested technique. While private keys provide a great deal of potential for varying user privacy, public keys are utilized to improve PAPR. This work examines the SCMA-OOFDM-NOMA physical layer security technology and introduces the dynamic QAM security mechanism for data transmission. This paper proposes a secure OOFDM technique based on chaotic coding and noise-masked key distribution.