The keychain reflects the general need: the keys must be easy to use and safe and compact to keep in the pocket.

However, bundling keys is a security issue. It is necessary to ensured that the administrations, keys and data contents of each subsystem of the bundle remain independent and separated from each other. For example, the conventional ID tag does not fit such a requirement; interdependencies break down the security of subsystems into a “tangle of doubts”. Instead, a mutual keychain of multiple locking systems fits nicely on a smart card by utilizing its internal firewall.

The Multi-ID concept is the foundation of a true IT age keychain; previously unseen data security and usage even easier than its mechanical predecessors'.

For example an office building; the security of the tenant premises', of the common areas and of the limited access premises remain independent of each other. Users only use “one tag as their keychain" throughout the entire property, and the solution also extends from one property to another, if needed. Everyone gain access where ever they need, but not elsewhere. Still, mistrust, cross-connections and data leakages are avoided.

Multi-ID also eliminates business risks, thus enabling new business propositions, such as “access control as a service”.