Signatures play a very important role in Suricata.
Suricata Rules consists of the following format:
https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Suricata_Rules
https://suricata.readthedocs.io/en/latest/rule-management/adding-your-own-rules.html
https://suricata.readthedocs.io/en/suricata-4.1.2/rules/intro.html
https://forum.netgate.com/topic/127428/suricata-custom-rules
https://www.admin-magazine.com/Articles/Detecting-intruders-with-Suricata/(offset)/3