code: func CryptoBackends() []string {
  	bes := make([]string, 0, len(cryptoNameToBackendMap))
  	for k := range cryptoNameToBackendMap {
  		bes = append(bes, k)
  	}
  	sort.Strings(bes)
  	return bes
  }
docs: // CryptoBackends returns the list of registered crypto backends.