Analysis of stealth communications over a public fiber-optical network.

We evaluate the security performance of the recently proposed "stealth" approach to covert communications over a public fiber-optical network. We present quantitative security analysis to assess the vulnerability of such systems against different attacks executed by an eavesdropper. We demonstrate the security advantage of the system by examining the BER/SNR performance as a function of the fidelity of the decoder used by an eavesdropper. Effective key length is constructed as a security metric to gauge the level of confidentiality implicit in the secure transmission.