Pseudorandom Frozen Bits Value and Index-Based Encrypted Constrained Polar Codes
Karim H. Moussa, Ahmed H. El-Sakka · 2024
Enhancing channel capacity in 5G and Future Systems with Polar Codes have proven to be an effective coding technique for achieving channel capacity in 5G and beyond. However, concerns about their security have prompted the de-velopment of an enhanced solution: the encrypted constrained polar code (ECPC) security system. This system leverages polar codes in conjunction with a pre-shared secret keyed to bolster security. The secret key plays a crucial role in generating random values and indices for frozen bits, resulting in a more secure and robust coding scheme. By separating input codeword bits into random indices with low mutual information and fixed ones, the coded sequences exhibit greater randomness, thereby influencing the frozen bit values and indices in the polarized coded bit channels. Simulations presented have demonstrated that the suggested ECPC system outperforms its predecessor, achieving more than double the Bit Error Rate (BER) performance at the same Eb/N0-Testing across different code word lengths, half code rates, and frozen bit restricted ratios consistently showed improved BER performance, underscoring the efficacy of the proposed system. Furthermore, security testing has revealed that a one-bit discrepancy between the decoding encryption key and the encoding key can lead to a significant increase in the receiver's BER probability. With the receiver unable to discern the sent material without the whole 232-bit symmetric encryption key, the ECPC system offers a heightened level of security in communication channels with improved performance.