It is about the configuration of DHE parameters for TLS handshake.
Before switching to Elytron my configuration of DHE in
$JAVA_HOME/security/java.security
jdk.tls.server.defaultDHEParameters= { \
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 \
29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD \
EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245 \
E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED \
EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D \
C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F \
83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D \
670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B \
E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 \
DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510 \
15728E5A 8AACAA68 FFFFFFFF FFFFFFFF, 2}
was used by wildfly12 during TLS-Handshake (Server Key Exchange). Everything worked fine.
After switching to Elytron my configuration parameter - the DHE module p - is no more used. Instead an other DHE module with half the size is used.
I need to have some option to configure the DHE parameter. Maybe I'm not seeing an existing option, maybe it is missing.
For my usecase I can not establish the TLS-connection because the TLS client does not accept Server Key Exchange with other DHE-Parameters than the above one.