code: @FFDCIgnore(NoSuchAlgorithmException.class)
      public static String createLookupKey(String realm, String userid, @Sensitive String password) {
          String lookupKey = null;
          if (realm != null && userid != null && password != null) {
              try {
                  String hashedPassword = getHashedPassword(password);
                  lookupKey = realm + KEY_SEPARATOR + userid + KEY_SEPARATOR + hashedPassword;
              } catch (NoSuchAlgorithmException e) {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
                      Tr.debug(tc, "There was a problem creating the lookup key.", e);
                  }
              }
          }
          return lookupKey;
      }
docs: Creates a lookup key to be used with the AuthCacheService.
  The parameters must not be null, otherwise a null key is returned.
  
  @param realm
  @param userid
  @param password
  @return