keyholder

Short definition from Wiktionary

Noun

1. 1
   One who holds the key for security reasons.
2. 2
   A device or component for holding a key.
3. 3
   The individual or organization with access to a cryptographic key.
4. 4
   A dominant partner who controls whether their submissive partner is able or allowed to orgasm or receive sexual stimulation, typically by locking the submissive partner in a chastity belt or chastity cage.