Explosive runes

Explosive runes was an arcane abjuration or alteration spell that booby-trapped written or drawn information to prevent unauthorized viewing.

Effects
This spell could be applied to written information in the form of a map, book, scroll, or a similar item containing written information. The abjuration version of this spell was limited to one object weighing 10 lb (4.5 kg) or less. The alteration version had no such limit and presumably could be used on dwarven runestones and the like. The caster traced the runes onto the document where they blended with the writing, remaining dormant until viewed by an unauthorized person. The caster and anyone he or she specifically gave instruction on how to bypass the runes could read the material safely.

When an unauthorized attempt to read the protected material was made, the runes exploded violently, damaging or destroying the warded writings and anyone within a 10 ft (3.1 m) radius. The reader  and those that were close enough to read the runes at the time of detonation took the full blast, while those that were just in the vicinity had a chance to resist or dodge part of the blast. The abjuration version of this spell exploded with magical force, the alteration version used magical fire.

Explosive runes were very difficult to detect using detect magic and rogues had to be very cautious when searching for and then disabling them. However, magical trap detection always gave a strong indication of their presence. The caster could remove the runes simply by dismissing them, but others required a successful dispel magic or erase spell. Any failure to remove the runes triggered the explosion.

Components
In addition to a verbal component, the caster had to touch the document being warded in order to trace the mystical runes. No material component was required.