> For the complete documentation index, see [llms.txt](https://docs.galactica.com/galactica-developer-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.galactica.com/galactica-developer-documentation/building-a-galactica-dapp/example-dapps/cypherbook.md).

# Cypherbook

The Galactica Cypherbook contains dApps to prove various basic statements about KYC and Social Media data.

It can be used as a basis for more complex dApps because the resulting Verification SBTs can be reused for other dApps requiring the same proofs.

## The proofs in the Cypherbook contain:

* Proving that a user has passed the KYC process.
* Proving that a user is at least 18 years.
* Proving that a user is a citizen of a non sanctioned country.
* Proving that a user is a non-US citizen.
* Proving that a user has a X/Twitter account created before 2020.
* Proving that a user has a X/Twitter account with at least 100/1k/10k followers.

## Code locations

* [Basic KYC circuit](https://github.com/Galactica-corp/galactica-monorepo/blob/main/packages/zk-certificates/circuits/zkKYC.circom)
* [KYC circuits for age and citizenship](https://github.com/Galactica-corp/galactica-monorepo/blob/main/packages/zk-certificates/circuits/ageCitizenshipKYC.circom)
* [Twitter follower count](https://github.com/Galactica-corp/galactica-monorepo/blob/main/packages/zk-certificates/circuits/twitterFollowersCountProof.circom)
* [Twitter creation time](https://github.com/Galactica-corp/galactica-monorepo/blob/main/packages/zk-certificates/circuits/twitterCreationTimeProof.circom)
* [Smart contracts](https://github.com/Galactica-corp/galactica-monorepo/tree/main/packages/zk-certificates/contracts/dapps)