Left invertibility of output-quantized systems: An application to cryptography

In this paper a secure communication method is proposed, based on left invertibility of output-quantized dynamical systems. The sender uses an output-quantized linear system with a feedback function to encode messages, which are sequences of inputs of the system. So left invertibility property enables the receiver to recover the messages. The secret key is formed by the system´s parameters, including the feedback function. The use of quantization makes the cryptographic system work exactly, and without asymptotic estimates. Simulations of encoding-decoding procedure and results about security of the method are finally shown.