PAIN is a military cybersecurity acronym.

PAIN stands for Privacy, Authentication, Integrity, Non-Repudiation

https://www.acronymfinder.com/Privacy%2c-Authentication%2c-Integrity%2c-Non_Repudiation-(PAIN).html

Cybersecurity- The Pyramid of Pain

https://rvasec.com/slides/2014/Bianco_Pyramid%20of%20Pain.pdf