Overview
Exchange contract allows users to exchange their assets, or upgrade metadata, depending on the specific mechanics used in the contract. The table below provides an overview of several common mechanics that use exchange functionality:
| Mechanics | Gives asset | Takes asset | Change metadata | Time delay | Random |
|---|---|---|---|---|---|
| CLAIM | ✖️ | ✔️ | ✖️ | ✖️ | ✖️ |
| PURCHASE | ✔️ | ✔️ | ✖️ | ✖️ | ✖️ |
| VESTING | ✔️ | ✖️ | ✖️ | ✔️ | ✖️ |
| STAKING | ✔️ | ✔️ | ✖️ | ✔️ | ✖️ |
| PONZI | ✔️ | ✔️ | ✖️ | ✔️ | ✖️ |
| BREED | ✔️ | ✔️ | ✖️ | ✖️ | ✔️ |
| CRAFT | ✔️ | ✔️ | ✖️ | ✖️ | ✖️ |
| DISMANTLE | ✔️ | ✔️ | ✖️ | ✖️ | ✖️ |
| MERGE | ✔️ | ✔️ | ✖️ | ✖️ | ✖️ |
| GRADE | ✔️ | ✖️ | ✔️ | ✖️ | ✖️ |
| MYSTERY BOX | ✔️ | ✖️ | ✖️ | ✖️ | ✔️ |
| LOOT BOX | ✔️ | ✖️ | ✖️ | ✖️ | ✔️ |
| RENT | ✖️ | ✖️ | ✔️ | ✖️ | ✖️ |
This list is not exhaustive, but it provides an idea of how exchange functionality is used in different mechanics. Here are some examples:
- BREED - mechanics involve the reproduction of NFT tokens by mixing the character's traits. This process is akin to genetic breeding, where the metadata of tokens is encrypted into genes from a mother and father. By mixing the traits of two existing tokens, a new token with mixed traits is created. The breeding mechanic adds an element of creativity and diversity to the token ecosystem, allowing for the generation of new and distinct tokens through the blending of existing ones.
- CLAIM - mechanics allow users to receive items from the system for free. One common use case of claim mechanics is the transfer of balances from an off-chain environment to an on-chain environment. This way user can redeem his in-game balance to his on-chain wallet. This mechanic is also used for distributing gifts and rewards from other mechanics such as Achievements.
- CRAFT - mechanic is similar to Purchase but could be used to spend all kind of tokens, not only currency. It is typically used to craft NFT items from semi-NFT resources
- GRADE - instantly changes token's metadata in exchange for currency tokens. Could be used for increase character's skills and item's level
- MYSTERYBOX - Mystery box adding an element of anticipation and surprise to the game. The item received from the box is predetermined but has random rarity.
- PURCHASE - mechanics is used for minting new NFT tokens in exchange for currency tokens
NOTE! When the user receives a ERC721, ERC998, or ERC1155 token, it will be minted, while NATIVE or ERC20 tokens will be spent from the merchants balance.
Security
All transactions must be signed off by the server before being executed on the blockchain. The server creates a signature containing the specific exchange details, including what the user should spend and what they should receive. The Exchange contract then verifies the signature and ensures that the signer has the necessary permissions and that the input arguments match the signature. If any of these checks fail, the transaction will be reverted.