> For the complete documentation index, see [llms.txt](https://qualitax.gitbook.io/interop/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://qualitax.gitbook.io/interop/bridging-approaches/mechanisms/hash-locking.md).

# Hash Locking

Hash locking, often associated with atomic swaps, involves the use of a cryptographic hash function to lock a transaction or a contract. To unlock and access the assets, the counterparty must provide the correct pre-image of the hash.

Through this process, if the trade doesn't complete, funds are returned after the timeout, and neither party is at risk of losing their assets.

1. A user locks their asset on Chain 1 by generating a secret and its corresponding hash.
2. The user initiates a transaction on Chain 2 with the hash, signaling their intent to swap.
3. Chain 2's contract (or another participant) verifies the hash lock and locks the corresponding asset on Chain 2.
4. To complete the swap, the user reveals the original secret on Chain 2, which unlocks the asset there.
5. This revealed secret can then be used on Chain 1 to unlock the initially locked asset.

HTLC Limitations:

<https://dl.acm.org/doi/abs/10.1145/3558535.3559786>


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