code: public void untrust() {
  		cache.updateEntry(cacheExpiryTime(), false, newRS, keepRS2, null);
  		delayedCacheUpdate = true;
  	}
docs: Notifies the ZRTP protocol that the user has revoked their trust in the
  connection. SAS verified flags is set to false and shared secrets with
  the remote end are removed from the cache.