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BitTorrent v2

blog.libtorrent.org

501–510 of 576 posts

Re: BitTorrent v2

#501

Earlier quoted context omitted.

It's been said that git, bittorrent, and proof-of-work were the three necessary prerequisites for the discovery of blockchains.

Don't forget: - Patricia-Merkle Trees proven in DC++ - DHT proven in eMule Kademlia

Many Gnutella clients were also using Merkle Trees by about 2002.

Re: BitTorrent v2

#502

I make P2P tools too. [0] Let me tell you this: Bittorrent is one of the few things in the space that actually ... works. It works not in the sense that there is a white paper that should work. Not in the sense that there are a few company-made swarms hosted on industrial servers that keep everyone up and alive, so that the thing gives the impression the 'P2P' network does work. Not in the sense that there is a very-…

Reminds me of one of the points Joel Spolsky made about peer-to-peer not being the reason Napster was successful:

https://www.joelonsoftware.com/2001/04/21/dont-let-architect...

> Your typical architecture astronaut will take a fact like “Napster is a peer-to-peer service for downloading music” and ignore everything but the architecture, thinking it’s interesting because it’s peer to peer, completely missing the point that it’s interesting because you can type the name of a song and listen to it right away.

> [...]

> If Napster wasn’t peer-to-peer but it did let you type the name of a song and then listen to it, it would have been just as popular.

Re: BitTorrent v2

#503
post #490
post #179

Earlier quoted context omitted.

I don't think so. 1. The user trusts the source of the .torrent file. 2. A malicious peer makes a preimage attack in some block in an executable file with contents containing some malicious executable payload. 3. The executable wasn't signed, or the targeted block must include executable headers. 4. Some peers get the malicious exe, some don't. The (2) step is still hard — preimage attacks on SHA1 are still expensive…

You're assuming a malicious peer, but what about a malicious seeder? One could take an existing unsigned executable, add in NOPs and no one would notice (same thing for certain noises in audio/video files). Since there's some control over the original hash value, executing step (4) is not exactly a preimage attack, it should be a bit easier.

If the seeder is malicious, there's no need to attack SHA1 at all. The seeder can't control which peers get which versions of any identical-SHA blocks — your target peer may share the bad block — so it seems easier to just upload the malicious content to everyone.

Re: BitTorrent v2

#504
post #363

Earlier quoted context omitted.

We already can: the "swap" will just be a v3 along the same lines.

Yeah, but would not they have to create v4, v5 and so forth every N years, for different hash functions?

Sure, but this is not any more expensive than any other versioning scheme you might be thinking of. Consider also that they got 19+ years out of v1, and that there is no reason to believe SHA2 will be broken faster than SHA1.

Re: BitTorrent v2

#505

Earlier quoted context omitted.

It’s great to live a in developed world during the peace time. Sometimes you have to transfer money in and out of the country at war with it’s currency in free fall and capital controls in place. At times like that “normal” ways take about 30% of the sum as transactional overhead, while bitcoin doesn’t. Sometimes “normal“ ways just don’t work normally. Sometimes your government is actively working against your abilit…

Does this hypothetical situation you describe exist anywhere outside of the hypothetical situation posited by a character in a Neal Stephenson novel? Seriously in reality the specifics of any sort of wild situation like the one you describe matter. Which countries? Which currency? Which kind of illegal behavior? And (I ask out of ignorance) in this scenario you describe why would whatever group managing whatever bitc…

Yes, what you call hypothetical situation is my daily life. The country where I live, Argentina, frequently imposes heavy restrictions on buying and selling foreign currencies. There is a hard monthly limit of $200 per person per month and there are talks of reducing the limit even further.

Sometimes crypto is the only way of sending/receiving money from other countries reliably and cheaply.

Other countries are much worse, Venezuela for instance has destroyed the value of their money, so bad that people use it wallpaper.

Re: BitTorrent v2

#506
Does anyone know any tutorial, article or any learning material related to creating BitTorrent-powered applications? Something simple, like sharing pictures or even text files.

Re: BitTorrent v2

#507

Earlier quoted context omitted.

It's nearly impossible to obfuscate a protocol to work around filtering. You'd want to look like some other protocol and you want that protocol be encrypted by default. Otherwise yours will get fingerprinted via the deep packet inspection. The most obvious choice is to run your protocol over TLS. But then they can just throttle long-lived bulky TLS connections where neither side is on 443. You can then require the re…

This is all true. The best way to make your application work now matter what filtering is in place is to disguise it as something which the ISP has to make work in order to get customers. Fundamentally, nothing has the same characteristics as BitTorrent - almost nothing has the same high uplink requirements, which is an absolute signature of BitTorrent traffic. Oh, also some of the shaping is implicit, not explicit.…

> almost nothing has the same high uplink requirements

Streaming video, whether that's a Skype conversation or showing your gameplay to Twitch, can be a pretty bulky upbound stream.

I wonder how fingerprintable those are, and if they have diverse enough endpoints to be able to disguise other traffic as them.

Re: BitTorrent v2

#509
post #504

Earlier quoted context omitted.

Yeah, but would not they have to create v4, v5 and so forth every N years, for different hash functions?

Sure, but this is not any more expensive than any other versioning scheme you might be thinking of. Consider also that they got 19+ years out of v1, and that there is no reason to believe SHA2 will be broken faster than SHA1.

Probably, but would it be possible to make it so that one could easily swap the hash function? Like I am curious about the details here. I think it would be. Clients probably will have to implement a couple of commonly used hash functions, and so forth. I am not sure how it would work in practice or if it is worth it at all. I am interested in all the details though.

Re: BitTorrent v2

#510
post #257

Earlier quoted context omitted.

It has been a few years, and despite a few attempts, I still don't really understand bitcoin. Yes yes ledgers and proof of work and yada yada, but I still don't know what I would need to do to buy something with bitcoin right now. As I understand I need to do something that's pretty much exactly like opening a bank account, but transactions take forever, they cost money, and the currency is not accepted by any busine…

Most people have no use for most currencies. I, for example, have no use for the Argentine peso. That doesn't make it useless for someone else, who might for example live in Argentina. The day you want to hire someone who wants their payment in Bitcoin for some reason, that's when you'll have use for it.

The Argentine peso is also useless to people living in Argentina.
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