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Trustchain is a ledger which is consensus-free. Forget anything you know about chains and ledgers. By using legally valid digital signatures it is possible to

Trustchain is a ledger which is consensus-free. Forget anything you know about chains and ledgers. By using legally valid digital signatures it is possible to sign agreements which are irrefutable. If you have two parties which sign a contract, it become legally enforceable. Trustchain requires that any block is signed by multiple parties and thus become legally enforceable. Every transaction forms its own "micro-block". Mono-signature transactions are strictly not allowed (e.g. Bitcoin,Ethereum approach). Once signatures are added to a block its valid: instant finality. Weird... Yes, it's a strange approach, even older then Bitcoin :-) Perhaps its useful. See "bandwidth-as-a-currency" news item in BBC News, 1 Sep 2007, http://news.bbc.co.uk/2/hi/technology/6971904.stm http://news.bbc.co.uk/2/hi/technology/6971904.stm Edit: no native token or money creation. Its just fabric for recording transaction micro-blocks. Non-profit. So nothing like Bitcoin at all. So works very well with dApps, Distributed Apps, no smart contracts needed. Scientific publication about Euros, DAO, dApps, passport-grade identity deployment: https://dl.acm.org/doi/abs/10.1145/3428662.3429744 https://dl.acm.org/doi/abs/10.1145/3428662.3429744

malikNF 6y ago
What's a "legally valid digital signature" in the context?
- synctext 6y ago
  Short answer: nobody knows yet. Its taking shape. UK minister of Digital infrastructure only some weeks ago announce their vision, far away from running code and new laws [1]. Dutch secretary-of-state on same days also send his digital ID vision to parliament [2]. [1] https://www.gov.uk/government/publications/the-uk-digital-identity-and-attributes-trust-framework https://www.gov.uk/government/publications/the-uk-digital-id... [2] https://www.tweedekamer.nl/kamerstukken/brieven_regering/detail?id=2021Z02985&did=2021D06488 https://www.tweedekamer.nl/kamerstukken/brieven_regering/det...
  - p_l 6y ago
    Well, in EU, there's existing digital signature law with (working) provisions for signing legally-binding contracts digitally... Maybe those are some new schemes under that framework?
    - pqs 6y ago
      I'm Spaniard. My national ID has a chip and I use it daily to sign documents with a card reader and a password. You can change your password at police stations that issue ID cards. The signature is legally valid.
littlestymaar 6y ago
So is there a reason to call it “blockchain” except for marketing reasons? (I'm currently working on a Paxos-based distributed system for an industrial application, and my client insist in calling that a “blockchain” in all internal communication because, you know “blockchain” sounds cool to them)
- synctext 6y ago
  Distributed ledger would be a better fit indeed. However, nobody then understands what it is. It offers tamper-proof micro-blocks, distributed validation, and leaderless governance. So this is more then idle marketing. But you're right, the name "Trustchain" is specifically tailored that government leaders and managers feel trustworthy and cool about it.
johanneskanybal 6y ago
I've dreamed of something like this too. I think it fills a good spot especially smaller transactions. I see parallels to the nordics bankid+swish, bank issued id/phone payment system. It's flawless in execution but both the id(!) and the payment part carries a cost picked up by the person accepting money (about $0.12 for each, very bank like). With your way of doing things none of the parts has to cost anything at the reasonable expense of potential double spending.
DJBunnies 6y ago
How does one rotate keys, in the event of compromise?
imtringued 6y ago
Isn't this just a digital check? People can tamper with their app and their checks will bounce once reality catches up.
- synctext 6y ago
  Yes, you need something against tampering. However, once you legally signed something, the contract/transaction is valid. Various mechanism can be used to ensure integrity. What we implemented specifically is that various witnesses can inspect your Trustchain blocks and co-sign your balance. So any node can act as a digital notary. You can also use a reputation or trust function. Here is a master thesis from Mathematics on distributed accounting systems. It contains numerous new mathematical proofs around integrity without strong identity assumption; .PDF "On the Sybil-Proofness of Accounting Mechanisms in P2P Networks", https://repository.tudelft.nl/islandora/object/uuid:6b4011c6-1668-4a1c-a49e-f86d226063b1 https://repository.tudelft.nl/islandora/object/uuid:6b4011c6...
  - bluesign 6y ago
    Problem is you cannot have offline and privacy (or better anonymity) at the same time. Reputation and trust can be gamed. Also requiring reputation will slow down adaptation. I will read this paper in the evening but I don't think you can have Sybil-Proof Accounting on P2P without some tradeoffs.
- throwaway4good 6y ago
  It would be wouldn't it? The double spend problem is not solved. And how could it be if it works offline. If I have a phone in some state s. Then I can just do the transaction and revert the phone's state back to s and spend the money again.
  - fbn79 6y ago
    I think they solved by using a banner on the app that say "Don't do It bad boy! Or I'll say it to your mum".
  - 6y ago
nixpulvis 6y ago
First of all, they clearly state the need for some amount of consensus here: https://tools.ietf.org/id/draft-pouwelse-trustchain-01.html#rfc.section.3.4 https://tools.ietf.org/id/draft-pouwelse-trustchain-01.html#... Second, if multiple parties are involved (I have to assume you mean more than just the needed 2 parties), wouldn't that mean you must be connected to a wider internet?

malikNF 6y ago

What's a "legally valid digital signature" in the context?

synctext 6y ago
Short answer: nobody knows yet. Its taking shape. UK minister of Digital infrastructure only some weeks ago announce their vision, far away from running code and new laws [1]. Dutch secretary-of-state on same days also send his digital ID vision to parliament [2]. [1] https://www.gov.uk/government/publications/the-uk-digital-identity-and-attributes-trust-framework https://www.gov.uk/government/publications/the-uk-digital-id... [2] https://www.tweedekamer.nl/kamerstukken/brieven_regering/detail?id=2021Z02985&did=2021D06488 https://www.tweedekamer.nl/kamerstukken/brieven_regering/det...
- p_l 6y ago
  Well, in EU, there's existing digital signature law with (working) provisions for signing legally-binding contracts digitally... Maybe those are some new schemes under that framework?
  - pqs 6y ago
    I'm Spaniard. My national ID has a chip and I use it daily to sign documents with a card reader and a password. You can change your password at police stations that issue ID cards. The signature is legally valid.

littlestymaar 6y ago

So is there a reason to call it “blockchain” except for marketing reasons? (I'm currently working on a Paxos-based distributed system for an industrial application, and my client insist in calling that a “blockchain” in all internal communication because, you know “blockchain” sounds cool to them)

synctext 6y ago
Distributed ledger would be a better fit indeed. However, nobody then understands what it is. It offers tamper-proof micro-blocks, distributed validation, and leaderless governance. So this is more then idle marketing. But you're right, the name "Trustchain" is specifically tailored that government leaders and managers feel trustworthy and cool about it.

johanneskanybal 6y ago

I've dreamed of something like this too. I think it fills a good spot especially smaller transactions. I see parallels to the nordics bankid+swish, bank issued id/phone payment system. It's flawless in execution but both the id(!) and the payment part carries a cost picked up by the person accepting money (about $0.12 for each, very bank like). With your way of doing things none of the parts has to cost anything at the reasonable expense of potential double spending.

DJBunnies 6y ago

How does one rotate keys, in the event of compromise?

imtringued 6y ago

Isn't this just a digital check? People can tamper with their app and their checks will bounce once reality catches up.

synctext 6y ago
Yes, you need something against tampering. However, once you legally signed something, the contract/transaction is valid. Various mechanism can be used to ensure integrity. What we implemented specifically is that various witnesses can inspect your Trustchain blocks and co-sign your balance. So any node can act as a digital notary. You can also use a reputation or trust function. Here is a master thesis from Mathematics on distributed accounting systems. It contains numerous new mathematical proofs around integrity without strong identity assumption; .PDF "On the Sybil-Proofness of Accounting Mechanisms in P2P Networks", https://repository.tudelft.nl/islandora/object/uuid:6b4011c6-1668-4a1c-a49e-f86d226063b1 https://repository.tudelft.nl/islandora/object/uuid:6b4011c6...
- bluesign 6y ago
  Problem is you cannot have offline and privacy (or better anonymity) at the same time. Reputation and trust can be gamed. Also requiring reputation will slow down adaptation. I will read this paper in the evening but I don't think you can have Sybil-Proof Accounting on P2P without some tradeoffs.
throwaway4good 6y ago
It would be wouldn't it? The double spend problem is not solved. And how could it be if it works offline. If I have a phone in some state s. Then I can just do the transaction and revert the phone's state back to s and spend the money again.
- fbn79 6y ago
  I think they solved by using a banner on the app that say "Don't do It bad boy! Or I'll say it to your mum".
- 6y ago

nixpulvis 6y ago

First of all, they clearly state the need for some amount of consensus here: https://tools.ietf.org/id/draft-pouwelse-trustchain-01.html#rfc.section.3.4 https://tools.ietf.org/id/draft-pouwelse-trustchain-01.html#... Second, if multiple parties are involved (I have to assume you mean more than just the needed 2 parties), wouldn't that mean you must be connected to a wider internet?