# Who actually secures a rollup: the security council problem

URL: https://www.caijing188.com/who-secures-a-rollup/
Published: 2026-10-19T00:09:39+08:00 | Updated: 2026-10-27T22:10:00+08:00
Verified: 2026-10-27

## Quick answer
The security guarantee of a rollup is not the fraud-proof window alone; it is the combination of an upgrade key, a timelock and a permissionless exit. Where those three are controlled by a small council, the practical trust model is closer to a custodian than the marketing implies.

## Summary
An optimistic rollup promises permissionless exit. In practice a small council can upgrade the bridge that holds your funds.

## Key takeaways
- Find the upgrade authority first.
- Check the timelock length in blocks.
- Confirm a permissionless exit exists.

## FAQ
Q: Does a 7-day challenge window protect me?
A: Only if you can exit without permission during it. If upgrades can be pushed faster than you can exit, the window is shorter than it looks.
Q: Is this unique to optimistic rollups?
A: No. Any system with an upgradeable bridge has an upgrade authority; the question is who holds it and what constrains them.