# Smart Contracts

## Legacy Smart Contracts that are a part of the 4thTech OCC Protocol v.1;

> `[Mails]` - used for encrypted data exchange over the blockchain; \
> `[Chat]` - used for encrypted short message exchange over the blockchain; \
> `[Users]` - used for the management of user-related on-chain data, and;\
> `[AppFeeManager]` - used for the management of application and fee-related data.

### 4P Smart Contracts;

> `[FOUR]` - ERC-20 token framework Smart Contract;\
> `[RTA]` - FOUR token right-to-access model Smart Contract.

### Decentralized storage NFT smart contracts;

> `[PX]` - Used to sync the key storage usage metrics.