On the outside, one sees it as a simple charm, however, the Fidelus Charm is immensely complex.It involves the concealment of a secret inside one's living soul. The information is hidden inside a chosen person, or Secret-Keeper, and is henceforth impossible to find unless the Secret-Keeper decides to divulge it.
If it so happens that the Secret-Keeper dies, the Fidelus Charm will still prove to work and manifest its miracles up to a period of time only, probably for a few days. Within the few days, a replacement has to be found and the charm has to be performed again. If not done so, the secret hidden will be visible.
In order for the Fidelus Charm to work, a few wizards are needed to combine powers together. It would be quite painful for the Secret-Keeper as the secret is concealed inside the soul, not the mind. The Charm can be shifted if one chooses to change the use of the Secret-Keeper or the place being hidden. This requires a same group of wizards to summon the charm out from the Secret-Keeper to make amendments.
