code: func (s *Store) OurKeyID(ctx context.Context) string {
  	for _, r := range s.Recipients(ctx) {
  		kl, err := s.crypto.FindPrivateKeys(ctx, r)
  		if err != nil || len(kl) < 1 {
  			continue
  		}
  		return kl[0]
  	}
  	return ""
  }
docs: // OurKeyID returns the key fingprint this user can use to access the store
  // (if any)