Opsec

• From Wikipedia (12-3-2020):

"Operations security (OPSEC) is a process that identifies critical information to determine if friendly actions can be observed by enemy intelligence, determines if information obtained by adversaries could be interpreted to be useful to them, and then executes selected measures that eliminate or reduce adversary exploitation of friendly critical information."

Within crypto it usually relates to how people and projects secure their private keys and/or their core smart contract. For instance with multisig and time locks.