9 ms·

Show HN: Very basic blockchain-free cryptocurrency PoC in Python

171 points by Graa 9y ago

imoskar 9y ago
Are there any blockchain-free cryptocurrencies currently on any exchange?
- fiatjaf 9y ago
  Ripple, Stellar.
- liopleurodon 9y ago
  maidsafe edit: I thought Ripple and Stellar had blockchains?
  - fiatjaf 9y ago
    They have "ledgers". Each ledger is based on the previous ledger, but the previous ones are discarded as soon as the next reaches a state of consensus. How does MaidSafe work, by the way?
    - RandomKid 9y ago
      > How does MaidSafe work, by the way? It consumes your $$$, and emissions promises that one day it'll become "a new shiny replacement of the Internet".
- wonderous 9y ago
  IOTA: https://coinmarketcap.com/currencies/iota/ https://coinmarketcap.com/currencies/iota/ Here's the related white paper: https://iota.org/IOTA_Whitepaper.pdf https://iota.org/IOTA_Whitepaper.pdf Website is here: https://iota.org https://iota.org
  - trome 9y ago
    Wow, their website literally murdered my browser, anyone have a JS;DR? I don't like my laptop sounding like its about to take off, considering it is usually silent...
  - antocv 9y ago
    Be warned about IOTA though, it still is not decentralized, see https://medium.com/@ercwl/iota-is-centralized-6289246e7b4d https://medium.com/@ercwl/iota-is-centralized-6289246e7b4d and the reaction of devs/foundation-members to that article, does resemble the reaction when somebody has something to hide. And https://www.reddit.com/r/Iota/comments/6jzfak/whats_wrong_with_iota/ https://www.reddit.com/r/Iota/comments/6jzfak/whats_wrong_wi... and some others, but also the official channels are moderated/censored. Seems to be more promise, hype abd marketing, than what it says on the tin.
    - sillysaurus3 9y ago
      The problem comes down to this; at the current stage, an attacker could very easily amass 33% of the hashpower of the network, because hashing only happens at the instants when new transactions are being added to the tree, and is completed in a second using a normal laptop. I was unable to find any information on how IOTA resolves this seemingly disturbing security issue on their website or in their whitepaper, but I did find the following information in two non-affiliated blogs (1, 2) after a lot of searching: > Milestones: Milestone is a special transaction issued by a special node called Coordinator. The Coordinator is run by Iota Foundation, its main purpose is to protect the network until it grows strong enough to sustain against a large scale attack from those who own GPUs. Milestones set general direction for the tangle growth and do some kind of checkpointing. Transactions (in)directly referenced by milestones are considered as confirmed. This means that IOTA in its current form does not provide any censorship resistance, since the path of the tree is centrally directed through a Coordinator node run by the IOTA Foundation. As such, IOTA is no more decentralized than an Apache Kafka cluster, or Ripple and their Unique Node List. I would argue that this is crucial information a user needs to know, yet I have no idea how the average person is intended to learn about this, since it’s nowhere to be found in the IOTA whitepaper or on their website. (EDIT: Since this article was written, IOTA published a post regarding this matter https://blog.iota.org/the-transparency-compendium-26aa5bb8e260 https://blog.iota.org/the-transparency-compendium-26aa5bb8e2.... I responded to their post https://medium.com/@ercwl/hello-david-b77bbc62c457 https://medium.com/@ercwl/hello-david-b77bbc62c457 )
- arisAlexis 9y ago
  byteball
- donquichotte 9y ago
  Stellar Lumen
  - bkolobara 9y ago
    Stellar has nice properties, like a decentralised exchange built into the platform and native integration with existing financial institutions/other cryptocurrencies through anchors. But I would not say it's blockchain-free. They close a "block" every 5 seconds. Depends on what you consider a block. They use boring stuff like PostgreSQL to store the data instead of reinventing everything.
    - fiatjaf 9y ago
      The innovation of blockchains is not on the how-to-store-things side, but how to keep a state of things every nodes agree with. Stellar can store data on Postgres because it is just a small database of how much money each account has at each ledger. Past ledgers can be erased from the database (which makes it not a blockchain in any sense anymore). Bitcoin has a history of all transactions organized in blocks not because it's a fancy new database technology, but because that way is the way it worked out better to keep a synced state between nodes, kind of an append-only log. You could, if you wanted that, read the Bitcoin database and translate it into a set of rows of a who-has-how-much Postgres table. Or, better, you could implement a Bitcoin client that stored its blocks as rows in a Postgres table, but I think it would be much more resource-intensive than the databases the Bitcoin clients are using today.
      - runeks 9y ago
        The Bitcoin blockchain is a compact serialization format used as the input to the proof-of-work function. The proof-of-work is the important part, and for that we need a centrally, agreed-upon serialization format where the latter blocks inherit PoW from earlier blocks. A Bitcoin node can store blocks/transactions in whatever way it wishes -- Postgres, Dropbox, SQLite DB on a floppy disk -- as long as it's able to deliver to nodes in the canonical serialization format, because it's needed to verify proof-of-work (and signatures for the transactions).
fiatjaf 9y ago
Yeah, I'm done with this "scientific" tone, this PDF thing and so on. What is in this paper that couldn't be posted as HTML in a web page? How is PDF better compared to that?
- mycomian 9y ago
  Are you trolling? It's a scientific paper.
  - detaro 9y ago
    He's right about those generally not actually needing PDF for non-print purposes though - simple text and a few images is way more web-friendly as HTML. Sadly only very few repositories make HTML versions available as well.
  - pollyannas 9y ago
    What makes it "scientific"? The fact that it is a PDF and the impersonal tone?
    - SolarNet 9y ago
      It was peer-reviewed and published in a journal. You are probably thinking of the advertising whitepapers of scammy alt-coins and crypto-tokens. This is actually research.
      - deleted 9y ago
        [deleted]
  - yosito 9y ago
    Are you trolling? HTML was invented for scientific papers.
    - literallycancer 9y ago
      Try reading the HTML version of Fielding's paper and tell me it looks better than the pdf. It might have been invented for that purpose, but that doesn't mean it's still suitable for it. When you are writing a paper, you want to control the presentation, not just the content.
pollyannas 9y ago
So this is basically a blockchain, but with transactions instead of blocks, and diverging-then-converging graph instead of a linear sequence of blocks (like a real family graph instead of just one-parent-one-child families common in blockchains). Looks nice, what are the problems with the approach? (the paper only lists the benefits).
- deleted 9y ago
  [deleted]
- tribler 9y ago
  can this handle a trivial Sybil attack? That seems to be the drawback of a graph or DAG-based approach. -ledger scientist
  - TeMPOraL 9y ago
    > ledger scientist That's a thing now? :o. Please explain :).
    - JBReefer 9y ago
      I'm not getting any results for it on DDG, might be a troll
      - _jn 9y ago
        Seems to be about someone creating massive amounts of privkeys and messing with verification (the fact that 51% attacks no longer exist in this approach make that irrelevant, however.) I'm not an expert on cryptocurrencies, but I don't see how that issue could be any more prevalent here than in "standard" (Bitcoin-style) blockchains.
        _jn 9y ago
        To expand on that: The only way I can imagine a Sybil attack here is if someone created a massive amount of tiny transactions, and the fees required to get peers to validate them would make that approach infeasible.
TD-Linux 9y ago
Note that base58 for addresses was generally considered a mistake - there's a replacement for Bitcoin proposed here: https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki https://github.com/bitcoin/bips/blob/master/bip-0173.mediawi...
- zik 9y ago
  Note that this proposal is from two authors who are under huge controversy right now and depending on who you listen to are likely to be removed from their current positions as Bitcoin contributors along with several others in the next few weeks. Given this it seems likely that this proposal will go nowhere.
deleted 9y ago
[deleted]
jchanimal 9y ago
Reminds me of a cryptocurrency for the gift economy that I'm working on. Each coin is unique and valued subjectively by each person. https://github.com/jchris/document-coin https://github.com/jchris/document-coin
- ErikBjare 9y ago
  Holy shit, I've had an idea just like that in the past.
  - Paul_S 9y ago
    I think it's a common idea. I thought of it before bitcoin was a thing (public signed transactions) and heard similar ideas many times. Still waiting for a working system because at this point in pretty sure I'll never actually create one myself.
Temasik 9y ago
the only public blockchain-free cryptocurrency in top 10 of coinmarketcap is iota www.iota.org

171 points by Graa 9y ago

imoskar 9y ago

Are there any blockchain-free cryptocurrencies currently on any exchange?

fiatjaf 9y ago
Ripple, Stellar.
liopleurodon 9y ago
maidsafe edit: I thought Ripple and Stellar had blockchains?
- fiatjaf 9y ago
  They have "ledgers". Each ledger is based on the previous ledger, but the previous ones are discarded as soon as the next reaches a state of consensus. How does MaidSafe work, by the way?
  - RandomKid 9y ago
    > How does MaidSafe work, by the way? It consumes your $$$, and emissions promises that one day it'll become "a new shiny replacement of the Internet".
wonderous 9y ago
IOTA: https://coinmarketcap.com/currencies/iota/ https://coinmarketcap.com/currencies/iota/ Here's the related white paper: https://iota.org/IOTA_Whitepaper.pdf https://iota.org/IOTA_Whitepaper.pdf Website is here: https://iota.org https://iota.org
- trome 9y ago
  Wow, their website literally murdered my browser, anyone have a JS;DR? I don't like my laptop sounding like its about to take off, considering it is usually silent...
- antocv 9y ago
  Be warned about IOTA though, it still is not decentralized, see https://medium.com/@ercwl/iota-is-centralized-6289246e7b4d https://medium.com/@ercwl/iota-is-centralized-6289246e7b4d and the reaction of devs/foundation-members to that article, does resemble the reaction when somebody has something to hide. And https://www.reddit.com/r/Iota/comments/6jzfak/whats_wrong_with_iota/ https://www.reddit.com/r/Iota/comments/6jzfak/whats_wrong_wi... and some others, but also the official channels are moderated/censored. Seems to be more promise, hype abd marketing, than what it says on the tin.
  - sillysaurus3 9y ago
    The problem comes down to this; at the current stage, an attacker could very easily amass 33% of the hashpower of the network, because hashing only happens at the instants when new transactions are being added to the tree, and is completed in a second using a normal laptop. I was unable to find any information on how IOTA resolves this seemingly disturbing security issue on their website or in their whitepaper, but I did find the following information in two non-affiliated blogs (1, 2) after a lot of searching: > Milestones: Milestone is a special transaction issued by a special node called Coordinator. The Coordinator is run by Iota Foundation, its main purpose is to protect the network until it grows strong enough to sustain against a large scale attack from those who own GPUs. Milestones set general direction for the tangle growth and do some kind of checkpointing. Transactions (in)directly referenced by milestones are considered as confirmed. This means that IOTA in its current form does not provide any censorship resistance, since the path of the tree is centrally directed through a Coordinator node run by the IOTA Foundation. As such, IOTA is no more decentralized than an Apache Kafka cluster, or Ripple and their Unique Node List. I would argue that this is crucial information a user needs to know, yet I have no idea how the average person is intended to learn about this, since it’s nowhere to be found in the IOTA whitepaper or on their website. (EDIT: Since this article was written, IOTA published a post regarding this matter https://blog.iota.org/the-transparency-compendium-26aa5bb8e260 https://blog.iota.org/the-transparency-compendium-26aa5bb8e2.... I responded to their post https://medium.com/@ercwl/hello-david-b77bbc62c457 https://medium.com/@ercwl/hello-david-b77bbc62c457 )
arisAlexis 9y ago
byteball
donquichotte 9y ago
Stellar Lumen
- bkolobara 9y ago
  Stellar has nice properties, like a decentralised exchange built into the platform and native integration with existing financial institutions/other cryptocurrencies through anchors. But I would not say it's blockchain-free. They close a "block" every 5 seconds. Depends on what you consider a block. They use boring stuff like PostgreSQL to store the data instead of reinventing everything.
  - fiatjaf 9y ago
    The innovation of blockchains is not on the how-to-store-things side, but how to keep a state of things every nodes agree with. Stellar can store data on Postgres because it is just a small database of how much money each account has at each ledger. Past ledgers can be erased from the database (which makes it not a blockchain in any sense anymore). Bitcoin has a history of all transactions organized in blocks not because it's a fancy new database technology, but because that way is the way it worked out better to keep a synced state between nodes, kind of an append-only log. You could, if you wanted that, read the Bitcoin database and translate it into a set of rows of a who-has-how-much Postgres table. Or, better, you could implement a Bitcoin client that stored its blocks as rows in a Postgres table, but I think it would be much more resource-intensive than the databases the Bitcoin clients are using today.
    - runeks 9y ago
      The Bitcoin blockchain is a compact serialization format used as the input to the proof-of-work function. The proof-of-work is the important part, and for that we need a centrally, agreed-upon serialization format where the latter blocks inherit PoW from earlier blocks. A Bitcoin node can store blocks/transactions in whatever way it wishes -- Postgres, Dropbox, SQLite DB on a floppy disk -- as long as it's able to deliver to nodes in the canonical serialization format, because it's needed to verify proof-of-work (and signatures for the transactions).

fiatjaf 9y ago

Yeah, I'm done with this "scientific" tone, this PDF thing and so on. What is in this paper that couldn't be posted as HTML in a web page? How is PDF better compared to that?

mycomian 9y ago
Are you trolling? It's a scientific paper.
- detaro 9y ago
  He's right about those generally not actually needing PDF for non-print purposes though - simple text and a few images is way more web-friendly as HTML. Sadly only very few repositories make HTML versions available as well.
- pollyannas 9y ago
  What makes it "scientific"? The fact that it is a PDF and the impersonal tone?
  - SolarNet 9y ago
    It was peer-reviewed and published in a journal. You are probably thinking of the advertising whitepapers of scammy alt-coins and crypto-tokens. This is actually research.
    - deleted 9y ago
      [deleted]
- yosito 9y ago
  Are you trolling? HTML was invented for scientific papers.
  - literallycancer 9y ago
    Try reading the HTML version of Fielding's paper and tell me it looks better than the pdf. It might have been invented for that purpose, but that doesn't mean it's still suitable for it. When you are writing a paper, you want to control the presentation, not just the content.

pollyannas 9y ago

So this is basically a blockchain, but with transactions instead of blocks, and diverging-then-converging graph instead of a linear sequence of blocks (like a real family graph instead of just one-parent-one-child families common in blockchains). Looks nice, what are the problems with the approach? (the paper only lists the benefits).

deleted 9y ago
[deleted]
tribler 9y ago
can this handle a trivial Sybil attack? That seems to be the drawback of a graph or DAG-based approach. -ledger scientist
- TeMPOraL 9y ago
  > ledger scientist That's a thing now? :o. Please explain :).
  - JBReefer 9y ago
    I'm not getting any results for it on DDG, might be a troll
    - _jn 9y ago
      Seems to be about someone creating massive amounts of privkeys and messing with verification (the fact that 51% attacks no longer exist in this approach make that irrelevant, however.) I'm not an expert on cryptocurrencies, but I don't see how that issue could be any more prevalent here than in "standard" (Bitcoin-style) blockchains.
      - _jn 9y ago
        To expand on that: The only way I can imagine a Sybil attack here is if someone created a massive amount of tiny transactions, and the fees required to get peers to validate them would make that approach infeasible.

TD-Linux 9y ago

Note that base58 for addresses was generally considered a mistake - there's a replacement for Bitcoin proposed here: https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki https://github.com/bitcoin/bips/blob/master/bip-0173.mediawi...

zik 9y ago
Note that this proposal is from two authors who are under huge controversy right now and depending on who you listen to are likely to be removed from their current positions as Bitcoin contributors along with several others in the next few weeks. Given this it seems likely that this proposal will go nowhere.

deleted 9y ago

[deleted]

jchanimal 9y ago

Reminds me of a cryptocurrency for the gift economy that I'm working on. Each coin is unique and valued subjectively by each person. https://github.com/jchris/document-coin https://github.com/jchris/document-coin

ErikBjare 9y ago
Holy shit, I've had an idea just like that in the past.
- Paul_S 9y ago
  I think it's a common idea. I thought of it before bitcoin was a thing (public signed transactions) and heard similar ideas many times. Still waiting for a working system because at this point in pretty sure I'll never actually create one myself.

Temasik 9y ago

the only public blockchain-free cryptocurrency in top 10 of coinmarketcap is iota www.iota.org