> For the complete documentation index, see [llms.txt](https://docs.sign.global/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sign.global/for-builders/advanced-topics.md).

# Advanced Topics

- [Cross Chain Attestations](https://docs.sign.global/for-builders/advanced-topics/cross-chain-attestations.md)
- [Hybrid Attestations](https://docs.sign.global/for-builders/advanced-topics/hybrid-attestations.md)
- [Schema Hooks](https://docs.sign.global/for-builders/advanced-topics/schema-hooks.md)
- [Tutorial: Checking Attestation Data](https://docs.sign.global/for-builders/advanced-topics/schema-hooks/tutorial-checking-attestation-data.md)
- [Schema Creation](https://docs.sign.global/for-builders/advanced-topics/schema-hooks/tutorial-checking-attestation-data/schema-creation.md)
- [Schema Hook](https://docs.sign.global/for-builders/advanced-topics/schema-hooks/tutorial-checking-attestation-data/schema-hook.md)
- [Creating an Attestation (Solidity)](https://docs.sign.global/for-builders/advanced-topics/schema-hooks/tutorial-checking-attestation-data/creating-an-attestation-solidity.md)
- [ZK Attestations](https://docs.sign.global/for-builders/advanced-topics/zk-attestations.md): Steps to integrate ZK verifiers into Sign Protocol's Schema Hooks.
- [Compile a Circuit](https://docs.sign.global/for-builders/advanced-topics/zk-attestations/compile-a-circuit.md)
- [Create a Schema Hook](https://docs.sign.global/for-builders/advanced-topics/zk-attestations/create-a-schema-hook.md)
- [Private Attestations](https://docs.sign.global/for-builders/advanced-topics/private-attestations.md): Private, encrypted attestations using Lit Protocol.