Mar 18 · 5 min read

The release of the fourth TAST Technical White Paper marks the end of our initial research phase. In this update we are summarising the findings and give an outlook on how we will go forward with TAST research. We are also happy to share with you that we developed a first research prototype for Pantos’ technology based on our scientific findings. Please note that the research prototype is a very early first iteration and is only intended to offer a first glimpse at what TAST could be able to do.

Summarising the findings of the first three TAST Technical White Papers

In the first TAST Technical White Paper we evaluated which blockchains and technologies are suitable for Pantos’ Token Atomic Swap Technology and which similar projects are currently being developed in the first TAST Technical White Paper.

After our initial research we focussed on how to solve the cross-chain proof problem. Every project trying to conduct cross-chain asset transfers faces this problem. As a solution, we presented and described the novel concept of claim-first transactions in the second TAST Technical White Paper.

In the third TAST Technical White Paper we addressed existing challenges of our concept of claim-first transactions. As a possible solution we presented a way of creating cryptographic Proof of Intent for cross-blockchain asset transfers, and propose the concept of deterministic witnesses, a solution for assigning witness rewards in claim-first transactions. In addition we also published a Q&A for the third TAST Technical White Paper, in which we explained our findings and solutions in an easier way.

Revisiting and answering our initial questions related to TAST

In the fourth TAST Technical White Paper, we revisit our review of the state of the art in blockchain technologies from nine months ago, and answer former open questions from today’s perspective in addition to discussing recent changes in the research field. We then give an overview of the contributions made within the TAST project, highlighting their relation to the open questions. Finally, we provide an outlook of current challenges and possible future work in the field of cross-blockchain technologies.

In the first TAST Technical White Paper we identified certain questions as general goals for TAST. We were able to answer those questions from today’s perspective. In the approaches we developed, cross-blockchain tokens do not need to have a specific issuing (minting) scheme. Our prototype uses fixed supply (predetermined by one specific minting account), however, none of the functionality introduced by cross-blockchain transfers is tied to the minting process. Therefore, in principle, any minting scheme currently found with tokens (fixed or variable supply) can be used with cross-blockchain tokens.

Currently, we destroy tokens on the source blockchain, and the balance of the source wallet is reduced. In order to ensure eventual consistency across blockchains despite the cross- blockchain proof problem, we employ a concept called claim-first transfers and described in our previous work. We also found out that smart contract functionality is required to a certain degree in order to realize cross-blockchain transfers. Our current approach uses Solidity. This is not a conceptual requirement, but care must be taken when examining the suitability of different smart contract platforms. For instance, our current approach makes extensive use of the signature creation and verification features of solidity, and such features must be supported by other smart contract platforms to facilitate cross-blockchain transfers as currently defined in TAST.

More questions and answers can be found in full version of the fourth TAST Technical White Paper, which can be found on TU Wien’s TAST homepage or you can download it directly here.

Release of the TAST research prototype on GitHub: ‘DeXTT: Deterministic Cross-Blockchain Token Transfers’

During the last ten months we made significant progress. We were able to reach our initial research goals and answer the most pressing questions we had after the first Technical White Paper. We published four Technical White Papers and developed a research prototype. You can find the research prototype plus an extensive documentation on the GitHub page. This research prototype serves as a reference implementation of the concepts discussed in our publications. The prototype uses claim-first transactions as well as deterministic witnesses, and is implemented in Solidity. The reference implementation has been used to verify the functionality of the concepts presented in the TAST publications (i.e., claim-first transfers and deterministic witnesses). Additionally, an extensive evaluation was performed using this prototype, the results of which are currently under peer review. The evaluation was performed in a multi-blockchain ecosystem testbed using geth in Proof-of-Authority (PoA) mode.

Outlook: Open questions and four more TAST Technical White Papers

While we made significant progress, there are still numerous open questions and challenges in the domain of cross-blockchain technologies. Further scientific groundwork is necessary on the concrete requirements with respect to smart contract functionality posed to blockchains in order to be able to process the type of cross-blockchain transactions proposed in our work.

In upcoming research, we will further simplify the approach presented in our latest paper, and we want to extend the functionality we have developed so far to enable additional, exciting features. For instance, we would like to enable smart contract invocations across blockchains. The basis we have developed so far seems very promising in this regard.

We are looking for talented developers

Here at Bitpanda and Pantos we are constantly looking for talented people to join our amazing teams. If you are interested, take a look at our career page if you want to work with us as for example PHP Backend Developer (m/f) or UI/UX Designer (m/f) and shape the future of the cryptocurrency industry.

About Pantos

As the first multi-blockchain token system, Pantos aims to bring blockchain projects closer together, improve communication between developers, researchers and users, and set innovative standards for cross-chain token transfers.

The goal is to serve as a lighthouse project in an increasingly fragmented blockchain space. With multiple blockchains serving all kinds of different purposes, Pantos is seeking to allow these projects to talk to one another in a standardised way. This will speed up innovation by creating a link between blockchains which then can scale together.

To get the latest news on the progress of the Pantos project you can follow our official channels:


The first multi-blockchain token system. Made with ♥ and care in Vienna by @bitpanda.


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The first multi-blockchain token system. Made with ♥ and care in Vienna by @bitpanda.



The first multi-blockchain token system. Made with ♥ and care in Vienna by @bitpanda.

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