We have written quite extensively about Point-Time-Locked-Contracts (PTLCs) in the past. PTLCs are an upgrade to the existing payment mechanism on the Lightning Network called Hash Time Locked Contracts (HTLCs). If you would like to learn more about PTLCs please see our previous blog post series.
We’ve built a proof of concept of PTLCs based on the Eclair Lightning implementation. The implementation uses ECDSA adaptor signatures. These are the same type of adaptor signatures used in the Discreet Log Contract specification and in our onchain PTLC demo.
https://github.com/bitcoin-s/eclair
With this code, you can now spin up Eclair nodes that are PTLC compatible. We have allocated a PTLC feature flag. Now if a custom Eclair node is connected to another node with this feature flag enabled, it will use PTLCs rather than HTLCs for payments.
Finally you can find detailed instructions for setting up local eclair nodes that can relay PTLC payments in the traditional Alice <-> Bob <-> Carol channel setup.
We believe that PTLCs are a cornerstone for building new financial products and services based on Lightning. We will continue to explore use cases for PTLCs and how they can be integrated with new Bitcoin DeFi protocols like DLCs. For an interesting example please read our previous blog post on Barrier Escrows and Barrier Escrows implemented using PTLCs.