安全与隐私eff.org
会或不会打印跟踪点的打印机列表
List of Printers Which Do or Do Not Display Tracking Dots
2010 — 2021，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
这是 EFF 维护的一份打印机清单，列出哪些彩色激光打印机在输出时会附带用于取证追踪的黄色点阵，哪些不会。清单作者后来提醒，第二代技术可能用抖动等方式生成不可见但仍可追踪的编码，因此很难确认市面上还有真正不做取证标记的打印机。
为什么经久不衰：它把隐蔽的打印机取证标记变成可查清单，并持续提醒人们：隐私风险不会因为看不见就消失。
HN 评论精选
列表作者指出第二代追踪技术可能不可见，因此清单未必能帮人买到无追踪打印机。
我写了这篇文章/最初创建了这个列表。我想强调，这项技术有第二代，可能使用抖动参数之类的方式，不产生可见点但仍生成追踪码。我们不知道细节，但知道一些公司告诉政府他们打算这样做；而政府机构称配合取证标记的公司，其一些较新打印机不再打印黄点。这让我觉得当初创建这个列表可能是个错误，因为清单的主要实际用途是帮人买不做取证追踪的彩色激光打印机，但不清楚是否真有这样的打印机在售。
schoen查看英文原文
I wrote this article/originally created this list, and I would like to emphasize that there is a second generation of this technology that probably uses dithering parameters or something of that sort, and that does not produce visible dots but still creates a tracking code. We don't know the details but we do know that some companies told governments that they were going to do this, and that some newer printers from companies that the government agencies said were onboard with forensic marking no longer print yellow dots. That makes me think that it may have been a mistake to create this list in the first place, because the main practical use of the list would be to help people buy color laser printers that don't do forensic tracking, yet it's not clear that any such printers are actually commercially available.
提问者想弄清追踪点的动机，以及它是否只能用于事后比对。
能否帮我澄清：1）厂商为什么这样做？是内部保修控制/追踪，还是有更广泛的联邦强制要求？2）这些点只用于事后分析，对吗？如果我打印了东西，然后有理由怀疑我，他们可以打印对比验证，但没有机制从初始文件找到打印机，对吗？
boredguy8查看英文原文
Can someone clarify for me: 1) Why do manufacturers do this? Is it for their own internal warranty control / tracking, or is there a broader federal mandate motivating this? 2) The dots are only useful in after-the-fact analysis, correct? If I print something and then there's reason to suspect me they can print something, compare, and verify, but there's no mechanism to find the initial document and find the printer, correct?
拔掉彩色墨盒可禁用已知追踪，比面对未知追踪更可控。
我宁愿选一台被列为有黄色追踪点的打印机，然后拔掉彩色墨盒。已知的安全措施比祈祷不存在未知措施更容易禁用。仍可能有冗余，但我认为概率较低——公司通常只会做最低限度来遵守这类指令。
marcus查看英文原文
I'd rather have one of the printers listed as having yellow tracking dots and yank out the color cartridges. Its easier to disable a security measure you know than praying there isn't a security measure you don't know. There is still a chance of a redundancy but I believe it is somewhat lower - as normally companies would do the bare minimum to comply with a directive like this one.
随机额外黄点或预印纸可混淆追踪码，降低可追溯性。
如果有个隐私打印应用，在文档里加随机黄点来混淆信息会很好。也许让几台不同打印机各印一个黄点就足够，然后把这张纸用于“真正”的打印。越想越觉得这甚至可以成为服务：让纸经过多台打印机，每次加上各自唯一标识，再出售分发。或者干脆用现金买打印机。
ProfessorLayton查看英文原文
It would be neat if there was a privacy printing app that added random yellow dots to a document to obscure the info. Perhaps simply printing a single yellow dot through a few different printers would be enough to accomplish the same thing. Then using the resulting paper for "real" prints. The more I think about it, this could even be a service. "Preprinted" paper that went though a bunch of printers, each adding their own unique identifier each time, then sold and distributed. That or just paying cash for a printer.
历次讨论
同类还值得读
非法素数
Illegal prime
维基百科条目，介绍“非法素数”：某些素数之所以被称为“非法”，是因为它们经特定编码后，恰好对应一段被法律禁止传播的数据——最著名的是 DVD 解密程序 DeCSS 的代码，有人把…
安全与隐私上首页 5 次 · 2010–2021en.wikipedia.org编辑精选关于 /dev/urandom 的常见误区
Myths about /dev/urandom
（Thomas Hühn 撰写，2014 年首发并持续更新）逐条反驳关于 /dev/urandom 的常见误解：它与 /dev/random 使用的是同一个 CSPRNG，一旦完…
安全与隐私上首页 5 次 · 2014–20202uo.de编辑精选AES 高级加密标准火柴人图解
A Stick Figure Guide to the Advanced Encryption Standard (AES)
一篇用火柴人漫画形式讲解 AES（高级加密标准）算法的经典科普文章。
安全与隐私上首页 5 次 · 2009–2022moserware.com编辑精选指纹是用户名，不是密码
Fingerprints are Usernames, not Passwords
作者（eCryptfs 维护者、Ubuntu 安全工程师）认为指纹等生物特征是公开、不可更改的标识，应视作用户名而非密码，不能当作秘密凭据用于认证。
安全与隐私上首页 4 次 · 2013–2017blog.dustinkirkland.comHTTPS 连接的最初几毫秒（2009）
The First Few Milliseconds of an HTTPS Connection (2009)
逐毫秒拆解一次 HTTPS 连接建立时发生了什么，重点讲 TLS 握手、证书验证、RSA 签名与密钥协商等机制，面向不熟悉该领域的读者。
安全与隐私上首页 4 次 · 2009–2020moserware.com编辑精选