内容来源：https://lifehacker.com/tech/what-is-tor?utm_medium=RSS

内容总结：

在当今数字时代，网络隐私已成为公众关注的焦点。许多网民发现，自己在浏览网页或使用社交媒体时，一举一动常被各类追踪器记录，形成个人画像并用于精准广告推送。然而，技术手段也为保护隐私提供了可能——其中，名为“Tor”的网络工具正受到越来越多注重隐私的用户青睐。

Tor（“洋葱路由器”的简称）的核心目标是为网络浏览提供匿名化保护，使他人无法轻易识别访问者的真实身份。该项目起源于上世纪90年代美国海军研究实验室，于2006年发展为非营利组织。如今，Tor不仅被生活在网络审查严格地区的公民、调查敏感事件的记者所使用，也吸引着众多普通隐私保护者。

Tor既指代匿名网络，也常指其官方浏览器。该浏览器基于Firefox改造，能自动将用户接入Tor网络，使用方法与普通浏览器无异。其工作原理在于：普通上网时，用户数据直接传至目标网站，IP地址等信息可能被多方获取；而Tor会将用户请求通过全球志愿者运营的多个节点接力转发，并在每一层传输中施加加密。每个节点只能解密单层信息，仅知晓相邻节点的位置，如同剥开洋葱般层层防护，最终实现访问者身份的隐藏。

尽管Tor能有效增强匿名性，但仍存在局限。其中，出口节点可能获知用户访问的目标网站（尽管无法追溯到源头），若网站未采用HTTPS加密协议，节点甚至可能窥见部分交互内容。不过，随着HTTPS的普及，此类风险已大幅降低。

值得注意的是，Tor常因可访问暗网而引发争议。实际上，暗网本身并非法外之地，它只是普通浏览器无法直接访问的网络空间，既存在非法内容，也包含合法活动。对普通用户而言，即使不接触暗网，Tor仍能帮助减少数字足迹，防止网络追踪。

使用Tor的代价主要体现在网速上。由于数据需经多节点跨国转发，加载网页的速度通常慢于常规浏览器。但目前Tor浏览器完全免费，支持Mac、Windows、Linux和安卓系统，用户可轻松尝试。对于担忧暗网关联的用户而言，只需主动避免访问相关资源，Tor的体验便与普通浏览器无异——除了稍慢一些，但换来的是更安心的隐私保护。

中文翻译：

互联网功能繁多，但对许多人而言，它远非私密空间。当你选择进入数字世界时，往往必须放弃匿名性：追踪器会监视你在网页浏览和社交媒体滚动时的每个举动，并利用这些信息构建你的身份画像（包括所处位置），为你推送更"相关"的广告。

但事情并非只能如此。有多种策略可以保护你的浏览隐私：你可以使用VPN让网络活动看起来源自其他地区；若使用Safari浏览器，可利用隐私中继功能向访问网站隐藏IP地址；或者，你还可以通过完全不同的网络连接互联网——Tor。

Tor是什么？

Tor（The Onion Router的缩写）的核心理念在于实现网络浏览匿名化，使任何人都无法识别访问特定网站的用户身份。Tor最初是20世纪90年代美国海军研究实验室的项目，2006年发展为非营利组织。此后，这个网络深受注重网络活动私密性的用户青睐，无论是严格审查制度国家的公民、处理敏感报道的记者，还是单纯重视隐私的个人。

Tor本身是一个网络，但常与该项目官方浏览器（同样称为Tor）相混淆。Tor浏览器是基于Firefox修改的版本，可连接至Tor网络。这款浏览器降低了使用Tor网络的技术门槛：你仍能像在Chrome或Edge中那样输入目标网址，但浏览器会自动通过Tor网络建立连接。这具体意味着什么？

Tor如何运作？

传统模式下，当你访问网站时，数据会连同身份标识信息（如设备IP地址）直接发送至目标网站。该网站、你的网络服务提供商及其他可能接触网络流量的实体都能识别发起请求的设备，并据此收集信息。这种行为可能只是网站为方便你下次访问而存储信息，也可能是网站通过网络追踪你的行迹。

Tor彻底颠覆了这种浏览模式。它不会将你的设备直接连向目标网站，而是让连接请求经过多个被称为"节点"的服务器。这些节点由全球志愿者托管，因此发起连接时无法预知请求会经过哪些节点。

但若仅依赖多节点跳转，Tor还不足以成为隐私保护的代名词。除节点系统外，Tor还会为请求添加多层加密。当请求在节点间传递时，每个节点只能解密一层加密信息，仅获取向下个节点发送请求所需的数据。这种方式确保系统中没有任何节点掌握过多信息：每个节点仅知晓上一步请求来源和下一步发送方向。这就像剥开洋葱的层层外皮，该平台由此得名。

以下简化示例说明其工作原理：假设你想通过Tor访问Lifehacker.com。像往常一样在地址栏输入网址并回车后，Tor会为请求添加分层加密。首个节点（可能位于美国）能解开一层加密，获知下一个节点的位置。第二个节点（可能位于日本）解密另一层加密后，将请求发往德国的第三个节点。这个第三节点（即出口节点）解密最终层加密，随即连接至Lifehacker.com。当Lifehacker收到请求后，反向流程启动：网站将数据发往德国节点，该节点重新添加加密层后传至日本节点，日本节点添加第二层加密再传回美国节点，美国节点添加最终加密层后才将完全加密的请求发回你的浏览器，由浏览器代为完成全部解密。恭喜：你已在不暴露身份的情况下访问了Lifehacker.com。

Tor并非完美的隐私工具

尽管Tor极大提升了网络活动匿名性，但无法提供完全保护。该网络最大弱点在于出口节点：由于链路末端节点携带解密后的请求，它既能获取你的访问目标，也可能窥见你在目标网站的行为。虽然无法追溯请求源头，但它能识别你正在访问Lifehacker。根据访问的网站类型，你可能泄露足够信息导致身份暴露。

这在网站普遍使用未加密HTTP协议时期尤为严重。若连接未加密网站，出口节点可能窥见你在该站的全部活动，包括登录信息、消息或财务数据。如今大多数网站已采用加密HTTPS协议，第三方窃取流量内容的风险显著降低。但即便追踪器无法精确掌握你在这些网站的行为，它们仍能记录你的访问痕迹，这就是Tor在当今加密互联网中依然有价值的原因。

谁应该使用Tor？

若对Tor有所耳闻，你可能知道它是访问暗网的首选服务。这没错，但Tor本身并非邪恶工具。暗网也非天生罪恶：它只是标准浏览器无法访问的网站网络集合。诚然其中存在许多充斥非法内容的站点，但也包含大量完全合法的活动。Chrome或Firefox无法浏览暗网，但Tor浏览器可以。

不过使用Tor不必非得访问暗网。任何希望保护网络流量隐私的人都能从中受益。你可能确实存在迫切需求，例如身处限制访问特定网站的国家，或是担心信息泄露引发连锁反应的调查记者。但即使没有特殊需求，Tor也能帮助普通人减少数字足迹，防止追踪器在网络上尾随你。

一个重要缺陷

若决定使用Tor，需明白其速度不及现代主流浏览器。让流量经过多个国际节点会拖累性能，网站加载时间可能比你习惯的要长。不过尝试使用无需任何费用，该浏览器完全免费支持Mac、Windows、Linux和Android系统下载使用（iOS用户暂不可用）。若对暗网传闻心存顾虑，请不必担心：只有主动寻找相关资源才会接触那些内容。除此之外，使用Tor的体验与普通浏览器别无二致——只是稍慢一些罢了。

英文来源：

The internet is many things, but for many of us, it is far from private. By choosing to engage with the digital world, you often must give up your anonymity: trackers watch your every move as your surf the web and scroll on social media sites, and they use that information to build profiles of who (and where) you are and deliver you more "relevant" ads.
It doesn't have to be this way. There are a number of tactics that can help keep your browsing private. You can use a VPN to make it look like your internet activity is coming from somewhere else; if you use Safari, you can take advantage of Private Relay to hide your IP address from websites you visit; or, you can connect the internet across a different network altogether: Tor.
What is Tor?
The whole idea behind Tor (which is short for The Onion Router) is to anonymize your internet browsing so that no one can tell that it is you visiting any particular website. Tor started out as a project of the U.S. Naval Research Lab in the 1990s, but developed into a nonprofit organization in 2006. Ever since, the network has been popular with users who want to privatize their web activity, whether they're citizens of countries with strict censorship laws, journalists working on sensitive stories, or simply privacy-focused individuals.
Tor is a network, but it's commonly conflated with the project's official browser, also known as Tor. The Tor Browser is a modified version of Firefox that connects to the Tor network. The browser removes many of the technical barriers to entry for the Tor network: You can still visit your desired URLs as you would in Chrome or Edge, but the browser will connect you to them automatically via the Tor network automatically. But what does that mean?
How does Tor work?
Traditionally, when you visit a website, your data is sent directly to that site, complete with your identifying information (i.e. your device's IP address). That website, your internet service provider, and any other entities that might be privy to your internet traffic can all see that it is your device making the request, and can collect that information accordingly. This can be as innocent as the website in question storing your details for your next visit, or as scummy as the site following you around the internet.
Tor flips the script on this internet browsing model. Rather than connect your device directly to the website you're visiting, Tor runs your connection through a number of different servers, known as "nodes." These nodes are hosted by volunteers all over the world, so there's no telling which nodes your request will go through when you initiate a connection.
But Tor would not be known for its privacy if it only relied on multiple nodes to bounce your traffic around. In addition to the nodes, Tor adds layers of encryption your request. When the request passes from one node to another, each node is only able to decrypt one layer of the encryption, just enough to learn where to send the next request to. This method ensures that no one node in the system knows too much: Each only knows where the request came from one step before, and where it is sending the request to in the following step. It's like peeling back layers of an onion, hence the platform's name.
Here's a simplified example of how it works: Let's say you want to visit Lifehacker.com through Tor. You initiate the request as you normally would, by typing the URL into Tor's address bar and hitting enter. When you do, Tor adds layered encryption to your request. The first node it sends it to, perhaps based in, say, the U.S., can unlock one layer of that encryption, which tells the node which node to send it to next. The next node, based perhaps in Japan, decrypts another layer of that encryption, which tells it to send it to a third node in Germany. That third node (known as the exit node) decrypts the final layer of encryption, which tells the node to connect to Lifehacker.com. Once Lifehacker receives the request, the reverse happens: Lifehacker sends the request to the node in Germany, which adds back its layer of encryption. It then sends it back to the node in Japan, which adds a second layer of encryption. It sends it back to the node in the U.S., which adds the final layer of encryption, before sending the fully encrypted request back to your browser, which can decrypt the entire request on your behalf. Congratulations: You have just visited Lifehacker.com, without revealing your identity.
Tor isn't perfect for privacy
While Tor goes a long way to anonymizing your internet activity, it won't protect you entirely. One of the network's biggest weaknesses is in the exit node: Since the final node in the chain carries the decrypted request, it can see where you're going, and, potentially, what you're doing when you get there. It won't be able to know where the request originated, but it can see that you're trying to access Lifehacker. Depending on what sites you're accessing, you might give enough information away to reveal yourself.
This was especially an issue when websites were largely using the unencrypted HTTP protocol. If you connected to an unencrypted website, that final node might be able to see your activity on the site itself, including login information, messages, or financial data. But now that most sites have switched to the encrypted HTTPS protocol, there's less concern with third-parties being able to access the contents of your traffic. Still, even if trackers can't see exactly what you're doing or saying on these sites, they can see you visited the site itself, which is why Tor is still useful in today's encrypted internet.
Who should use Tor?
If you've heard anything about Tor, you might know it as the go-to service for accessing the dark web. That is true, but that doesn't make Tor bad. The dark web is not inherently bad, either: It's simply a network of sites that cannot be accessed by standard web browsers. That includes a number of very bad sites filled with very bad stuff, to be sure. But it also encompasses a number of perfectly legal activities as well. Chrome or Firefox cannot see dark web sites, but Tor browser can.
But you don't need to visit the dark web in order for Tor to be useful. Anyone who wants to keep their internet traffic private from the world can benefit. You might have a serious need for this, such as if you live in a country that won't let you access certain websites, or if you're a reporter working on a story that could have ramifications should the information leak. But you don't need to have a specialized case to benefit. Tor can help reduce anyone's digital footprint, and keep trackers from following you around the internet.
One big drawback
If you do decide to use Tor, understand that it won't be as fast as other modern browsers. Running your traffic through multiple international nodes takes a toll on performance, so you may be waiting a bit longer for your websites to load than you're used to. However, it won't cost you anything to try it, as the browser is completely free to download and use on Mac, Windows, Linux, and Android. (Sorry, iOS fans.) If you're worried about what you've heard about the dark web, don't be: The only way to access that material it is to seek it out directly. Otherwise, using Tor will feel just like using any other browser—albeit just a tad slower.