I think I understand what he wants. And it is doable. However, this requires far more than a simple MSN Messenger addon (note: a plugin for Messenger Plus! isn't what you want
). It also requires a whole parent controlled secured environment in Windows as people (children) could otherwise startup and use whatever they want and thus making the intended software and addon rather useless.
As said, a plugin for Messenger Plus! isn't what you want. It has far too many restrictions in what can be done. Such thing should be made as a direct MSN Messenger addon (or even better as a whole worksuite restricting access etc in Windows where MSN Messenger is just a part of it).
Also note that Microsoft itself is in process of developping something like that which involves digital passports. Experiments with this are done in countries which have digital (chipcard) passport IDs or which are in the process of replacing the traditional passports with chipcards (eg: Belgium). The digital passports will be used as a means to identify over the net and to login in for example MSN Messenger.
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