> ## Documentation Index
> Fetch the complete documentation index at: https://docs.patchwork.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Freezing & locking

> Understand the freezing & locking mechanics that ensure metadata integrity

## Freezing

Freezing is the process of locking data and/or relations so that a Patchwork721 can be sold or transferred with data guaranteed intact.

Patchwork enables inherited ownership models between assignees and fragments. Without freezing, a malicious actor could sell an assignee and frontrun the transaction with an unassign call, stripping away some value off of the NFT to be sold.

Related functions from `IPatchwork721`

```solidity theme={null}
getFreezeNonce(uint256 tokenId)
setFrozen(uint256 tokenId, bool frozen_)
frozen(uint256 tokenId);
transferFromWithFreezeNonce(address from, address to, uint256 tokenId, uint256 nonce)
safeTransferFromWithFreezeNonce(address from, address to, uint256 tokenId, uint256 nonce)
safeTransferFromWithFreezeNonce(address from, address to, uint256 tokenId, bytes memory data, uint256 nonce)
```

*Workflow*

1. The owner will call `setFrozen(myTokenId, true)` to freeze the NFT.
2. The third party (marketplace) will call `getFreezeNonce(myTokenId)` to get the current freeze nonce.
3. The third party (marketplace) will call `safeTransferFromWithFreezeNonce()` providing the known freeze nonce to transfer.

If the nonce at transfer is higher than expected, the transfer will revert.

A `Frozen` or `Thawed` event are emitted when frozen state changes

## Locking

Locking prevents an NFT from being assigned or transferred.

```solidity theme={null}
setLocked(uint256 tokenId, bool locked_)
locked(uint256 tokenId)
```

An IERC5192 `Locked` or `Unlocked` event are emitted when locked state changes