Hello friends and fellow professionals.
I am continuing to share short excerpts from my upcoming book as it comes together, especially the parts that challenge assumptions we rarely question in modern systems.
11 Controls for Zero-Trust Architecture in AI-to-AI Multi-Agent Systems
This excerpt comes from Control 3, which focuses on something most architectures still treat as an afterthought: time.
Control 3: Time-Based Access Management
Time-based access control answers a question that most systems never ask: when should an action be allowed at all. In autonomous environments, timing is more than scheduling. It is a security boundary. Permissions that make sense in one moment can be dangerous in the next, and agents that operate continuously will act without hesitation unless the system teaches them that time itself matters. Temporal controls bring order to that flow. They define windows of safety, enforce automatic expiration, tighten permissions during instability, and ensure that no authority survives longer than it should. This chapter explores how time becomes a governing signal in Zero Trust, and why every permission, no matter how small, must exist inside a defined and continuously verified timeline.
3.1 Temporal Access as a Security Boundary
Threats
Identity verification establishes who made the request. Authorization determines what they are allowed to do. But neither control answers a question that becomes critical in autonomous systems: when should this action be allowed, and does the current moment still justify it?
That gap opens the door to an entire class of attacks.
Replay attacks are the oldest version of this problem. An attacker captures a legitimate, signed, fully authorized message, then replays it hours or days later. If the system cannot detect stale intent, the replayed message is accepted as fresh and legitimate.
Time-bomb attacks follow the same pattern. A compromised agent plants legitimate instructions that will execute long after its access has been revoked. If the system only checks permissions at creation time but not at execution time, those instructions still run.
Credential reuse creates a similar risk. Long-lived tokens give attackers a broad window of opportunity. A stolen credential may remain valid across entirely different operational states. If the system assumes that a credential issued yesterday is still meaningful today, it collapses under its own trust assumptions.
Context drift pushes the threat surface even further. Permissions often make sense only under certain environmental conditions. A sensitive operation might be safe during staffed hours but dangerous during overnight automation. If the system doesn’t revalidate context when the action is attempted, old permissions get applied to new conditions that no longer support them.
All of these attacks share one thing in common:
they weaponize the gap between when authorization is issued and when it is used.
This control ends up being one of the most misunderstood pieces of Zero Trust, especially in agent-based systems where actions are fast, autonomous, and continuous. Time is not just metadata. It is part of the trust decision itself.
More excerpts coming soon.
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