Show HN: My experimental take on a decentralized ledger

repomies691 10 years ago |

Needs a brief documentation "how it works" or something... I really don't understand the concept, I'm very familiar with bitcoin and somewhat familiar with ripple/stellar. How is the ledger maintained? How do we form the consensus on the valid ledger? What are the incentives for running nodes? etc.

ianpurton 10 years ago |

How would this prevent a flood attack ? What I mean is in Bitcoin and presumably Stellar, you need coins to create transactions. There is therefore a cost to spamming the system.

buhrmi 10 years ago | |

It doesn't prevent a flood attack. The challenge in this approach does not lie in "preventing it" but in "dealing with it".

herendin 10 years ago | | |

Do you have some ideas on how to deal with it?

buhrmi 10 years ago | | |

Yeah

oafitupa 10 years ago | |

Stellar is 100% centralized. In fact, its owners took it down at some point to change some rules.

devit 10 years ago |

It's interesting that it says that "Warning: Requires Postgres 9.5. You WILL lose sync if you run against an earlier version. YOU HAVE BEEN WARNED."

Which PostgreSQL features new in 9.5 are being used that cause that? Or are earlier versions somehow buggy?

buhrmi 10 years ago | |

I'm using upserts... The reason I'm using upserts is basically just lazyness because I didn't feel like refactoring the source code to work around requiring upserts. Also, I'm not very confident in C++ so I did not want to take on that task.

opendomain 10 years ago | | |

You can fix this with basic SQL

IF record EXISTS then UPDATE else INSERT

anarazel 10 years ago | | |

No. Conccurrency makes it way harder than that.

devit 10 years ago | | |

In PostgreSQL, you can set the SERIALIZABLE isolation level for the whole database, put a retry loop around all database transactions and completely stop worrying about concurrency issues.

I think all database applications should be written like this at least until performance starts being an issue.

anarazel 10 years ago | | |

Entirely depends on the the type of workload / application architecture. In some cases the rollback ratios will be massive (I've seen 70%). In other cases adding such a retry loop is unattractive because the latency jitter. Or retaining all involved data for a retry is unattrictive.

Yet Another problem is that you need to enforce all sessions potentially involved in a data race need to use serializable; that can be easy or hard, depending on the scenario.

jpgvm 10 years ago | | |

Use UPSERT, it's correct -and- fast rather than just correct.

Increasing the transaction isolation level shouldn't be done out of laziness.

joeyspn 10 years ago |

> Transactions are FREE (the fee is always zero)

How would you deal with DDoS attacks? Taking down a ledger like this could be easy...

buhrmi 10 years ago | |

> How would you deal with DDoS attacks?

That's the open question.

deckar01 10 years ago | |

Cloudflare doesn't have to charge a fee for every http request, although transaction fees do seem like the elegant solution.

Karunamon 10 years ago | | |

Cloudflare is a massive, well-funded, centralized entity.

kushti 10 years ago |

How is it protected from Sybil attacks on consensus algo? The algo description is definitely needed.

jgeerts 10 years ago |

Is there any interesting lecture that got you this far or did you study source code?

BinaryResult 10 years ago |

Check out https://morph.is/v0.8/ if you haven't seen it, decentralized encrypted file storage and email, exciting stuff.

explorigin 10 years ago | |

> Distributed Spam Proof Mail! Uncensorable, inherently spam proof and transparently encrypted and sender authenticated messaging! Secure enough for Edward Snowden! Easy and fool-proof enough for a child!

43 exclamation points on the front page. He has the hype cranked up pretty high. Still, it's nice to see all of these P2P efforts.

misiti3780 10 years ago | |

very cool! thanks!

col_rad 10 years ago |

Cool. I really liked the idea of Stellar, but I just cant get over the premined coin distribution. Nice to have a truly decentralized alternative!

oafitupa 10 years ago | |

What do you like about Stellar? It's not decentralized at all. Being premined is just the icing on the cake.

col_rad 10 years ago | | |

Stellar is indeed decentralized but not distributed [1]. What I like about Stellar is the concept of gateways and trust. It adds a whole new dimension for transactions.

[1] http://web.cs.ucla.edu/classes/cs217/Baran64.pdf

zamalek 10 years ago |

Basically, `Bitcoin - Politics`. A nice idea.

tinco 10 years ago | |

It's also `Bitcoin - all_the_hard_problems_bitcoin_solves`. Still nice but you can't compare it with Bitcoin. This is more the sort of service banks could use to track loans.