Fountain-Coding-Aided Secure Delivery via Cross-locking between Payload Data and Control Information

The conventional fountain-coding aided strategies realize transmission secrecy by ensuring the legitimate user to receive the sufficient number of fountain-coded packets ahead of the eavesdropper does, which emphasise on the security of entire file. However, in the process of communication a fraction of confidential message will be recovered by parts of correct decoding of intercepted packets at the eavesdropper, which is forbidden for some scenarios with stringent security requirement. To solve the above mentioned issue, we propose a secure transmission scheme via cross-locking between the fountain-coded data and the codebook information, in which the generating matrix of fountain codes is implicitly transferred between legitimate pairs such that the inter-data codebook information can be protected. Specifically, the transmitter exploits fountain-coded packets legitimate user received to encrypt the key associated with the generating matrix to prevent eavesdropper from decoding any coded packets, thereby the secure transmission is guaranteed. A wireless secure transmission system based on the proposed scheme is developed on the software radio platform and its security performance is evaluated in actual scenarios. The experimental results prove that the proposed scheme outperforms the comparison schemes in the matter of the intercept probability and the recovering proportion for eavesdropper.