> For the complete documentation index, see [llms.txt](https://zkcross-network-1.gitbook.io/learn.zkcross.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zkcross-network-1.gitbook.io/learn.zkcross.network/security-and-control/signing-and-permissioning.md).

# Signing and Permissioning

Deterministic rules define what is allowed. Signing defines what is physically possible.

zkCross treats signing as a controlled permission surface rather than as a generic execution key.

### Permissioned signing

Only policy-compliant actions can reach the signing path.

The signing model is designed so that:

* approval is scoped to allowed actions, targets and parameters
* keys are never exposed in application logic
* signatures cannot authorise arbitrary execution outside approved action sets
* privileged operations can require stronger approval conditions

Where appropriate, zkCross uses MPC-based signing. In non-EVM contexts such as ICP, decentralised signing primitives can be used while preserving the same high-level security model.

The important architectural point is that signing remains downstream of policy validation. Guardian approval without valid signing is insufficient. Signing without policy compliance is impossible.

That separation prevents permission escalation through hidden call paths or loosely scoped authorisation.