Thanks Sharat, yes the article confirms.
So I appear to have options to try:
set security macsec connectivity-association NAME security-mode static-cak
set security macsec connectivity-association NAME pre-shared-key ckn <key>
set security macsec connectivity-association NAME pre-shared-key cak <key>
set security macsec interfaces ae0 connectivity-association NAME
#or
set security macsec connectivity-association NAME security-mode static-cak
set security macsec connectivity-association NAME pre-shared-key ckn <key>
set security macsec connectivity-association NAME pre-shared-key cak <key>
set security macsec interfaces xe-0/2/0 connectivity-association NAME
set security macsec interfaces xe-0/2/1 connectivity-association NAME
#or
set security macsec connectivity-association NAME security-mode static-cak
set security macsec connectivity-association NAME pre-shared-key ckn <key>
set security macsec connectivity-association NAME pre-shared-key cak <key>
set security macsec interfaces xe-0/2/0 connectivity-association NAME
set security macsec interfaces xe-0/2/1 connectivity-association NAME
set security macsec interfaces ae0 connectivity-association NAME