Crumb Update / crumb restriction

[Santhosh Kumar]

Team,

Using crumb value, remote job trigger is working with curl -X post. We need to understand 2 things here. 

1. Is this crumb value static for 1 user/1 session.

2. How can i update the crumb if i want to change it for unauthorized access.[For example every 3 months].

Regards,

Santhosh P