Our analysis so far focussed only on software encryption techniques. We have found that at least with respect to power consumption, encrypting everything in software is infeasible. However, this may not be the case when we consider a separate hardware encryption unit on network interface cards. Encryption in hardware can be done significantly faster than in software and at a constant rate of energy consumption irrespective of the general purpose computational device to which it is attached. We performed a literature survey of existing optimized implementations of encryption algorithms and analyzed how the cost of incorporating an independent hardware encryption unit compares with the cost of typical network interfaces. From the data available from Counterpane Labs, Twofish may be implemented in hardware using about 8000 gates for an encryption rate of 32Mbps and 19000 gates for an encryption rate of 160 Mbps. It turns out that with the state of the art fabrication technology such encryption units can be easily implemented at costs within a dollar. Hence, this certainly points to a cost effective integration of encryption cards into network interfaces. We hope to probe this aspect further in our future work.