Grant Proposal: Sia Atomic Swap with Adaptor Signatures Feasibility Study

Project Name: Sia Atomic Swap with Adaptor Signatures Feasibility Study

Name of Organization Submitting Proposal : UTXO BV (Komodo Platform Developers )

Purpose of the Grant: Currently, Sia does not have a function for HTLC which is required for doing cross-chain atomic swaps, the purpose of this grant is to conduct a feasibility study to estimate development of the technology to allow Sia’s adaptor signatures to be able to be used in atomic swaps, specifically in the Atomicdex protocol.

If the findings are amenable to the Sia Foundation and community we will submit another grant proposal for the full time and cost of development

Code contributions will be made open source.

Timeline: 1 Month


Deliver feasibility report to Sia Foundation on the estimate of cost and development for enabling atomic swaps via adaptor signatures against many different cryptocurrencies and platforms. This will include: Estimate of Cost, Developer Hours and other considerations regarding development of this technology.

Budget: $10,000 USD or equivalent

Budget will go towards developers to conduct the investigation.


We will report to the Sia Foundation our findings. Additionally we will need to have discussion with Sia developers about some of the nuances of how Sia works on a low level and open channels of communication between Sia and Komodo developers for questions that may arise.


A big yes from me on this one. I also hope if that this turns into a no based on the research, it can be made to be supported, that the foundation tries to do what’s needed to support, as this is a start to a long-term critical need for Sia’s liquidity and survival.


Great to see movement on this. Another thumbs up.

I wholeheartedly support this research as integrating sia and atomic swap can create a decentralized exchange for sia, which holds immense value for the long-term potential and expansion of the sia ecosystem.

roadie (building on Schnorr work done by Hyperspace) has previously demonstrated that SC<->ETH atomic swaps are possible (albeit unergonomic and expensive — Ed25519 requires a lot of gas!). How does AtomicDEX compare to this in terms of functionality?


Sounds good to me.

Do your civic duty and cast your vote, fellow community comrades!

Sounds great. Make it happen!

Will be Siafunds supported too along with the plan of SC integration?

Hello KMD,

The committee has reviewed and approved this proposal, congratulations!

Please note, the committee would appreciate an answer to Foundation president Luke’s question found here, namely asking how this project differs from the previous research done in the roadie project, and what improvements AtomicDEX might offer.

Please reach out on the Sia Foundation community Discord server or provide an email address to get in touch with us so we can provide you with the documents to begin your exciting project!

Kino on behalf of the Sia Foundation and Grants Committee

Hello KMD,

Hey there team, we’d like to see if the recent Atomic Wallet hack compromised the security of the Atomic DEX at all.

Additionally, please be sure to reach out to us as per our previous post to get the ball rolling on your grant!

Kino on behalf of the Sia Foundation and Grants Committee


Thank you for reaching out, for some reason I was not getting updates. I will reach out to you promptly. Apologies for the late reply.

The Atomic Wallet hack that has happened recently does not affect Atomicdex in any way. They are two separate pieces of software . We do not have any connections with Atomic Wallet.

Unfortunately , the swaps due to the signature scheme will be expensive compared to HTLC swaps. However with Atomicdex, atomic swap functionality would extend beyond just ETH into a dozen and half other EVM chains as well as dozens of UTXO coins.

My email is . I will reach out via Discord as well ( handle: polycryptoblog ) so we can get the ball rolling. Looking forward to seeing what all is needed to bring atomic swap technology to Sia!

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Hey all, We wanted to touch base and ask a few questions regarding the deliverables.

We are wrapping up our initial research and resource gathering needed for the feasibility study, and we will be shifting towards preparing the presentation.

We are realizing that introducing the necessary logic for Hash Locked Time Contracts(HLTCs) to SIA’s consensus code would result in a significantly easier route towards DEX integrations. This can be done via the existing “UnlockConditions” mechanism by adding an additional signature algorithm that executes HLTC logic rather than any kind of signature verification. We are also aware that this mechanism will eventually be replaced with the “Spend Policy” mechanism. Introducing an HLTC spend policy to this mechanism seems to be a very straight forward development task as well.

Our current viewpoint(certainly subject to change in the final study) is that adaptor signatures, specifically secp256k1<->ed25519 adaptor signatures, are a feasible way of executing atomic swaps between BTC-like blockchains and SIA, but the integrations needed to introduce this functionality to any existing DEX technology stack will be significantly more resource intensive(namely dev hours and 3rd party audits of novel cryptography) than forking SIA’s consensus code to introduce HLTC-like logic.

Shall we continue the study with the majority focus on the adaptor signature route or could we widen the scope to “What is the simplest or most cost effective path towards SIA integration into existing DEXs”. We would still outline the necessary components and development work for the adaptor signature route, but we would also explore the feasibility and costs of other options, namely forking SIA’s consensus code to introduce true HLTC-like functionality.

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We’re definitely open to introducing an HLTC spend policy. IIUC this would be pretty straightforward to implement, though it might require changing the definition of V2SiacoinInput in order to include a hash preimage. A concrete specification would be a great outcome for this grant.

Hello Sia Community,

Progress on the Sia Atomic Swap with Adaptor Signatures Feasibility Study is going well. We expect to have a document ready for review this week. We are open to discussing the findings in a call with the committee if desired.

Hey Sia Atomic team, Luke has obviously responded here but we’re just officially confirming the committee’s approval to widen the scope as requested.

Hello, we have finalized the work and uploaded all relevant files to:

We’re excited for any feedback or questions. Thanks for the opportunity.