keys of the kingdom

Noun

keys to the kingdom pl (plural only)

1. (idiomatic, plural, plural-only) A resource, usually information or knowledge, the possession of which gives the possessor access to power.
   • This fortress, from its strong position, was considered as one of the keys to the kingdom, and had belonged to the Earl of March, a disappointed candidate for the crown, who had now attached himself to the banner of England.1830, John Donald Carrick, Life of Sir William Wallace of Elderslie, page 112