JDG upgraded to JGroups 3.6.10 recently. Since 3.6.10 ENCRYPT protocol is deprecated and SYM_ENCRYPT or ASYM_ENCRYPT should be used instead (see JGroups manual for details). However, JDG user guide still recommends ENCRYPT. This needs to be fixed. Please note that most of the text can be used also for SYM_ENCRYTP, but there are still some minor differences like SYM_ENCRYPT uses keystore_name instead of key_store_name used in ENCRYPT.

Also there should be clear warning, that ENCRYPT is deprecated and shouldn't be used. Also probably worth mentioning that when using ENCRYPT protocol, uses can experinced ArrayIndexOutOfBoundsException, see JGRP-2088 for details - and again, switching to SYM_ENCRYPT solves the issue.