系统与基础设施blog.libtorrent.org
BitTorrent v2
BitTorrent v2
2020 — 2022，它一次次回到首页
黑点是上首页（≥ 50 分）的那次投稿，空心点是没冲上去的投稿，点越大分数越高。
导读
libtorrent 作者 Arvid Norberg 介绍 BitTorrent v2 协议规范：改用 SHA-256 哈希、为每个文件构建 Merkle 哈希树、采用可变分块大小等改进，以提升安全性并减少重复数据。文章还说明了 v1/v2 混合种子（hybrid torrent）的兼容设计。
为什么经久不衰：BitTorrent 是少数真正大规模运转的 P2P 协议，v2 的内容寻址设计让不同种子间相同文件可互通 peers，对种子的长期健康意义重大，至今仍是协议演进的重要参考。
HN 评论精选
BitTorrent 胜在真正可用、不靠营销，是 P2P 开发的典范
我也做 P2P 工具。说实话，BitTorrent 是这个领域里少数真正“能用”的东西。它不是靠白皮书、不是靠公司架设的服务器撑起 swarm、也不是靠 Web 3.0 的营销话术。它是装到你电脑上就能为你干活的工具。它不吹嘘自己是 P2P——P2P 不是卖点，只是它恰好的工作方式，这正是所有 P2P 开发者应当追求的境界。
rolleiflex查看英文原文
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-well oiled marketing machinery talking about Web 3.0 that allows its founder to go on TechCrunch and talk about the upcoming distributed paradise. Bittorrent works in the way you install it into your computer and it does something for you. And for that alone, it has my immense respect and attention. It's a tool that doesn't pitch that it's a P2P tool - it doesn't try to convince you with sob stories about how using P2P helps fight against the big bad evil web. Instead, you use it because it's genuinely the best at what it does: it being P2P is not a selling point, it's just how it happens to work, and that is exactly what it should be. That is something all P2P developers should aspire towards. [0] Aether P2P: https://getaether.net
跨种子的相同文件可共享 peers，是提升种子长期存活的重要特性
等等，跨 swarm 的内容寻址 blob……这是否意味着完全不同的人在不同时间制作的种子，只要碰巧包含相同文件，就能互相受益于对方的 peers？如果是这样，这将显著提升大量种子的长期健康度，让更多 peers 互助。
tomxor查看英文原文
> not only uses a hash tree, but it forms a hash tree for every file in the torrent [...] > Files that are identical can also more easily be identified across different swarms, since their root hash only depends on the content of the file. Wait, content addressed blobs across swarms... does that mean torrents made by completely different people at different times that happen to contain one or more identical files can benefit from each other's peers? If so this feels like a significant feature that would boost the long term health of a lot of torrents and connect more peers that could be helping each other.
qBittorrent 4.4 带来 v2 支持，建议支持 v1 种子升级为混合种子
我猜这次被翻出来是因为 qBittorrent 刚发布 4.4 版，内置 libtorrent 2.x，从而支持 BitTorrent v2。希望 trackers 能尽快出现混合种子/磁力链接。另外希望客户端允许用户把已完整做种的 v1 种子升级为混合种子，让分散在旧种子里的 peers 互通。
nodja查看英文原文
I assume this is being posted because qBittorrent recently released version 4.4 which includes libtorrent 2.x and therefore support for BitTorrent v2. Hopefully we'll start seeing hybrid torrents/magnets in trackers soon. Although these are mostly automated so I'm not sure how fast the tools will catchup. One thing I'd like qBittorrent and other torrent clients to do is to allow users to upgrade v1 torrents to hybrid torrents if they're fully seeded, this would allow cross polination for old torrents where peers are scattered between the original torrent and batch torrents, or where trackers add extra files causing the v1 hash to change.
遗憾 v2 未解决 ISP 识别和限速 BT 流量的问题
感觉这次升级的步子不够大。要是 BitTorrent v2 能让 ISP 更难识别 BT 流量就好了——AT&T 会人为限制上传速度。
proverbialbunny查看英文原文
It feels like this isn't a large enough leap forward. It would be nice if BitTorrent v2 made it harder for ISPs to identify what is bit torrent traffic. AT&T artificially slows down upload speeds.
历次讨论
同类还值得读
TTY 揭秘（2008）
The TTY demystified (2008)
经典文章深入剖析了 Unix/Linux 中 TTY 子系统的工作原理，包括线路规程、终端驱动、信号与控制字符等机制。
系统与基础设施上首页 11 次 · 2009–2025linusakesson.net编辑精选为什么 GNU grep 这么快
Why GNU grep is Fast
FreeBSD 邮件列表上一篇广为流传的帖子，解释 GNU grep 为什么快：核心在于 Boyer-Moore 字符串搜索算法配合精心优化的内部循环和 I/O，让程序在搜索时“…
系统与基础设施上首页 9 次 · 2010–2022lists.freebsd.orgXplain：为普通人讲解 X11
Xplain – Explaining X11 for the rest of us
《Xplain》是作者（HN 用户 Jasper_）写的一系列 X11 长文，用他在浏览器中重建的 X11 绘图模型做交互演示，讲解 X11 的绘图模型与窗口系统设计。
系统与基础设施上首页 6 次 · 2013–2020magcius.github.io编辑精选旋风教程：为 Linux 创建极小 ELF 可执行文件（1999）
A Whirlwind Tutorial on Creating Really Teensy ELF Executables for Linux (1999)
breadbox 写于 1999 年的经典教程，主题是如何为 Linux 手工构造并裁剪出体积极小的 ELF 可执行文件。
系统与基础设施上首页 6 次 · 2007–2025muppetlabs.comPostgreSQL 内部原理
The internals of PostgreSQL
《The Internals of PostgreSQL》是一本免费在线书籍，系统讲解 PostgreSQL 的内部实现，包括查询处理、并发控制、WAL、缓冲区管理等核心机制。
系统与基础设施上首页 5 次 · 2017–2025interdb.jp编辑精选