Discretionary Access Control (DAC)
An access model where the resource's owner decides who else gets access — the model behind file permissions on nearly every operating system.
aka: DAC
DAC’s defining trait is also its original sin: because any owner can grant access at will, there’s no way to guarantee data won’t leak sideways once it’s shared — the classic “trojan horse” problem, where a program running with your permissions can quietly copy your files somewhere an attacker controls. It’s simple and flexible, which is exactly why it doesn’t scale to environments where access needs to follow an enforced, centrally-audited policy.