尽管我们尽我们最大努力提供好的工具,让你可以在使用计算机时保护你的隐私, 但在这个复杂问题上还没有哪种魔幻的或完美的解决方案。 理解好这样的工具的局限性,是决定 Tails是否适合你的第一步;第二步,就是要好好利用它。

Tails does not protect against compromised hardware

如果计算机被人通过物理访问的方式入侵了,并安装了不信任的硬件(如键盘记录器),那么用 Tails 也可能不安全了。

Tails can be compromised if installed or plugged in untrusted systems

通常你启动 Tails时的计算机本来的系统里的病毒是不会破坏 Tails的,但是:

  • Tails 应被安装在信任的系统上。 否则它可能在安装时崩溃。

  • Plugging your Tails USB stick in a compromised operating system might corrupt your Tails installation, and destroy the protection that Tails provides. Only use your Tails USB stick to start Tails.

See the corresponding FAQ.

Tails does not protect against BIOS or firmware attacks

Tails 也不可能抵挡通过 BIOS或其他嵌入进固件的攻击。 这些攻击并不由操作系统直接掌管或提供。 没有一个操作系统能抵挡得了这样的攻击。

举个例子, 这个 对 BIOS的攻击,来自 LegbaCore

Tor exit nodes can eavesdrop on communications

Tor 只是用来隐匿你的地理位置,而非加密你的通讯。

与其通常的流量都是直接从来源地路由到目的地, 使用 Tor网络的通讯会走几个随机的 Tor节点,进而掩盖了你的踪迹。 所以在任一个单一点上的观察者都无法说出数据从哪里来,或到哪里去。

一个Tor 连接穿过3个节点, 其中最后一个才与最终目的地建立了实质的连接

The last relay on this circuit, called the exit node, is the one that establishes the actual connection to the destination server. As Tor does not, and by design cannot, encrypt the traffic between an exit node and the destination server, any exit node is in a position to capture any traffic passing through it. See Tor FAQ: Can exit nodes eavesdrop on communications?.

举例,在2007年,一个安全研究员拦截了数千个由世界各地驻外使领馆官员和人权组织发出的私人邮件,通过窥探由他自己运行的出口节点的连接。 参见 Wired: 流氓节点把 Tor匿名网络转成偷窥者的天堂


Tails 包含了很多工具能帮你使用强加密, 用于浏览网页,发邮件和聊天时。在我们的 关于 网页上都有显示。

Tails makes it clear that you are using Tor and probably Tails

Your Internet Service Provider (ISP) or your local network administrator can see that you're connecting to a Tor relay, and not a normal web server for example. Using Tor bridges in certain conditions can help you hide the fact that you are using Tor.

The destination server that you are contacting through Tor can know whether your communication comes from a Tor exit node by consulting the publicly available list of exit nodes that might contact it. For example using the Tor Bulk Exit List tool from the Tor Project.

所以用 Tails 并不让你看上去像随便一个互联网用户一样。 Tor 和 Tails 所提供的匿名性会让所有使用 Tor的用户看起来是一样的, 所以不可能区分得出来是谁在其中。

也请看 我能不让别人知道我在使用 Tails吗?

Man-in-the-middle attacks

中间人攻击(MitM)是一种主动窥探的形式,攻击者与受害者之间建立独立的连接,并在他们中间作中继, 让他们相信他们彼此在直接地通过私有连接通讯, 而实际上这通讯被攻击者控制着。

用 Tor的时候,中间人攻击也可以发生在出口节点和目标服务器之间。 出口节点自己也可以成为一个中间人。 举个这种攻击的例子,见 MW-Blog: TOR 出口节点做 MITM攻击

再说一次,要从这些攻击中保护你自己你需要使用端对端加密 并且同时十二分小心验证服务器的真实性。

Usually, this is automatically done through SSL certificates checked by your browser against a given set of recognized certificate authorities). If you get a security exception message such as this one you might be the victim of a man-in-the-middle attack and should not bypass the warning unless you have another trusted way of checking the certificate's fingerprint with the people running the service.




Later in 2011, DigiNotar, a Dutch SSL certificate company, incorrectly issued certificates to a malicious party or parties. Later on, it came to light that they were apparently compromised months before, perhaps as far back as May of 2009, or even earlier. Rogue certificates were issued for domains such as google.com, mozilla.org, torproject.org, login.yahoo.com and many more. See The Tor Project: The DigiNotar Debacle, and what you should do about it.

这仍然会给“中间人攻击” 机会 ,尽管 你的浏览器信任了一个 HTTPS 连接。

一方面,Tor 通过提供匿名性让针对某个特定的人的中间人攻击变得很困难,这种攻击方式采用含糊的SSL证书。但另一方面,Tor 使得运行了出口节点的个人或组织能执行大规模的中间人攻击,或发起对特定服务器的攻击,尤其是那些刚好流经这台服务器的Tor用户。

引自 Wikipedia: Man-in-the-middle attack, Wikipedia: Comodo Group#Certificate hackingTor 项目:检测证书签发机构的漏洞和浏览器 的共谋

End-to-end correlation attacks

Tor is designed for low-latency communications: the time for a request to go from your computer to the destination server and back is generally less than 1 second. Such a low latency makes it possible to use Tor for web browsing and instant messaging.

As a consequence of Tor being designed for low-latency communications, an attacker could in theory correlate the timing and shape of the traffic entering and exiting the Tor network to deanonymize Tor users. Such attacks are called end-to-end correlation attacks, because they require observing both ends of a Tor circuit at the same time.

For example, an ISP and a website could potentially collaborate to deanonymize a Tor user by observing that the same particular network traffic pattern enters the Tor network at the ISP and then reaches the website shortly afterward.

End-to-end correlation attacks have been studied in many research papers but we are not aware of any actual use to deanonymize Tor users. In the past, law enforcement agencies preferred exploiting vulnerabilities in Tor Browser and Tails to deanonymize users instead of performing end-to-end correlation attacks.

Tails protects better than Tor Browser from such software vulnerabilities but does not protect better from end-to-end correlation attacks.

See also:

Tails doesn't encrypt your documents by default

The documents that you might save on storage devices are not encrypted by default, except in the Persistent Storage, which is entirely encrypted. But Tails provides you with tools to encrypt your documents, such as GnuPG, or encrypt your storage devices, such as LUKS.

It is also likely that the files you might create will contain evidence that they were created using Tails.

If you need to access the local hard-disks of the computer you are using, be conscious that you might then leave traces of your activities with Tails on it.

Tails doesn't clear the metadata of your documents for you and doesn't encrypt the Subject: and other headers of your encrypted email messages

很多文件格式在文件中放置了隐藏的数据或元数据。Word 或 PDF 文件会存作者名、文件创建日期,有时还有一些文件的编辑历史,这取决于文件格式以及所使用的软件。

还有请注意,你的 OpenPGP 加密邮件并不加密标题和其他的头部行。这不是 Tails 或 OpenPGP协议的缺陷;这是因为要兼容原始的 SMTP协议。不幸的是现在还没有针对标题栏加密的 RFC 标准。

图像文件格式,像 TIFF或JPEG,在隐藏数据方面大概是最出名了。这些由数码相机或手机创建的文件,包含一种元数据格式叫 EXIF,能包含照片拍照时的日期、时间、GPS记录、拍照设备的品牌和序列号,还有原始图像的缩略图。图像处理软件都倾向保留这些元数据不变。因特网就充满着裁减过的或模糊化的图像,但其中的 EXIF 和缩略图 还是原始图像的。

Tails doesn't clear the metadata of your files for you. Yet. Still it's in Tails' design goal to help you do that. For example, Tails already comes with the Metadata anonymisation toolkit.

Use Tails sessions for one purpose at a time

For example, don't use the same Tails session to both check your work email and anonymously publish a document. That is, unless you're OK with an adversary being able to correlate those tasks.

Adversaries could relate different tasks done in a Tails session by:

  • Analyzing your Tor circuits

    Tails and the Tor Browser naturally connect to different websites via different circuits in the Tor network. But if you connect to the same website several times in one session, like logging into two accounts on the same social media website, Tails and the Tor Browser use the same circuit. This website could then link those activities by noting that they come from the same Tor circuit.

    To ensure you use new Tor circuits for Internet traffic:

    • If you only use the Tor Browser to connect to the Internet, you can click its New Identity button to create a new circuit.
    • If you use multiple applications, you can restart Tails.

    For more about how Tor does or does not preserve anonymity, see the Tor Project's support pages.

  • Gaining access to your Persistent Storage

    You can prevent the information in your Persistent Storage from being linked to other activities by switching between several USB sticks that run Tails. That way the Persistent Storage of, say, your activist email in Thunderbird can be kept separate from your use of Tails for work.

    We also recommend this step if you worry about someone gaining physical access to your computer or USB sticks. This is particularly a concern if you have to use Tails on an insecure or public computer, because Tails can't protect against compromised hardware.

Tails doesn't make your crappy passwords stronger

Tor 让你在网上保持匿名;Tails 让你不在电脑上留下痕迹。但再说一遍,它们都不是什么确保信息安全的万能药

如果你用了弱密码,攻击者可以暴力破解,不管你用没用 Tails。想知道你的密码是否是弱密码 以及想学习如何设立一个更好的密码,可以阅读:Wikipedia: Weak Passwords

Tails is a work in progress

Tails 以及它包含的所有软件,都还在持续开发中,有可能还有错误或安全漏洞。