This spell prevented even the caster from opening a chest or passing through a door or portal that had been secured. The only known means for removing this spell were by a successful dispel magic, powerful spells such as limited wish, or potent magic items like chimes of opening. Otherwise, the object was impervious to fire, cold, electricity, and knock, as well as spells that altered the material of the protected area, such as dig, reduce, transmute rock to mud, and vanish. Any attempt to place a glyph, rune, or symbol on the secured object resulted in immediate triggering or detonation of those effects. If detect magic or similar divination spells are used, they would register strong alteration magic in the area protected by this spell.
This spell was permanent until dispelled and could be applied to one chest or an area up to 10 ft2 (0.93 m2) per level of the caster. In addition to its other protections, the object or area was impervious to physical damage for a number of minutes equal to the caster's level. After that, the object or area could be successfully damaged by physical force and eventually destroyed. Secure did not prevent dimension hopping, so a dimension door or similar movement spell could get through a protected door or portal, but, in the case of a portal, a dimensional traveler would not be taken to the portal's destination, merely to the other side of the portal.
In addition to verbal and somatic components, this spell required something small made of iron and a semi-precious gem of any type.