Taking seriously the independent living system approach implies that we must make as few assumptions about the `outside world' as we reasonably can, and be as self-reliant as we can. This caution extends through all levels of the system and along multiple dimensions. One approach would simply avoid all external influences, but when it comes to communications and communications risk, fundamentally we are damned if we do and damned if we don't: We might have had warning of a threat in time to avoid it, had we been allowing external factors to affect system behavior.
Most work in computer-based communication has focused on efficiency and power rather than safety. High-speed communications protocols, for example, can now supply data as fast or faster than most processes are ready to digest it, and even the ubiquitous TCP/IP internet protocol requires reacting to a connection attempt even just to ignore it, leading in part to the `denial of service' attacks currently occurring on the internet. Similarly, nearly all software for personal computers focuses heavily on adding ever more programmed abilities and `features,' even as automated network access is woven more deeply into the system rather than being more isolated, with the predictable results that your own computer's processing and data can be stolen out from underneath you by anyone simply by `speaking' to your machine in particular ways.
Natural living systems have a large variety of mechanisms for evaluating interactions, assigning degrees of trust, and allowing only limited influences in proportion to estimated risk. Complex chemical signals and hard-to-duplicate bird songs, for example, increase confidence that messages are genuine; between ccr worlds cryptography serves that purpose, among others, helping on the one hand to establish identity and increasing (in particular) the sender's cost to generate a valid message on the other hand.
Ritualized interactions such as mating behaviors allow gradual and mutual stepping-up of trust and acceptable risk as confidence in identities and intentions grows. A ccr world wishing to communicate, likewise, engages in protocols designed to capture as much of the value of communication as possible while exposing the world to as little risk as possible. Here, we describe a few of those protocols and mechanisms, to provide concrete examples of living computation design strategies in artificial systems.