Secure Multiplex Coding with Dependent and Non-Uniform Multiple Messages
This work addresses practical limitations in secure communication systems for scenarios where secret messages are dependent or non-uniform, offering incremental improvements over previous methods.
The paper tackled the problem of removing the restrictive assumption of independent and uniform distributions for multiple secret messages in secure multiplex coding, achieving this by generalizing the channel resolvability technique and providing practical construction methods using error-correcting codes and channel-universal coding.
The secure multiplex coding (SMC) is a technique to remove rate loss in the coding for wire-tap channels and broadcast channels with confidential messages caused by the inclusion of random bits into transmitted signals. SMC replaces the random bits by other meaningful secret messages, and a collection of secret messages serves as the random bits to hide the rest of messages. In the previous researches, multiple secret messages were assumed to have independent and uniform distributions, which is difficult to be ensured in practice. We remove this restrictive assumption by a generalization of the channel resolvability technique. We also give practical construction techniques for SMC by using an arbitrary given error-correcting code as an ingredient, and channel-universal coding of SMC. By using the same principle as the channel-universal SMC, we give coding for the broadcast channel with confidential messages universal to both channel and source distributions.