STRLCPY/link-lock

Link to post and add hidden-bookmarks README
Jacob Strieb committed 3 years ago

032b5f7b

1 parent 09fb92a7

■ ■ ■ ■ ■ ■

hidden/README.md

1	+	# Bookmark Knocking: Hidden Bookmarks Without a Browser Extension
2	+
3	+	Click special bookmarks in the right order to open a hidden link.
4	+
5	+	- [Try the demo](https://jstrieb.github.io/projects/hidden-bookmarks/#demo)
6	+
7	+	---
8	+
9	+	# Introduction
10	+
11	+	Imagine that you want to propose to your partner, but they sometimes use your
12	+	computer. You don't want them to see that you are bookmarking wedding rings.
13	+	What do you do?
14	+
15	+	Alternatively, imagine you live with someone abusive. You decide to get help,
16	+	so you look for resources on the Internet. There are helpful links, but you
17	+	know if you bookmark them and your abuser goes through your computer, they may
18	+	find them. You can't install a hidden bookmark extension either, because they
19	+	could just as easily notice that. What do you do? Unfortunately, this is a
20	+	[realistic scenario for many
21	+	people](https://www.nytimes.com/wirecutter/blog/domestic-abusers-can-control-your-devices-heres-how-to-fight-back/).
22	+
23	+	Almost a year ago, I created [Link Lock](https://jstrieb.github.io/link-lock)
24	+	-- a tool to enable anyone to securely password-protect URLs. But adding a
25	+	password to links isn't always enough.
26	+
27	+	Link Lock relies on strong cryptography for security, but sometimes a layer of
28	+	obscurity is a practical necessity. In other words, there are some situations
29	+	where a bookmark that asks for a password is too suspicious to be useful, even
30	+	if the password protection is secure.
31	+
32	+	Bookmark knocking is a novel technique to address this problem. It enables
33	+	users to hide bookmarks using features already built into every web browser.
34	+	There are two versions available:
35	+
36	+	- [A stable, simplified version integrated directly into Link
37	+	Lock](https://jstrieb.github.io/link-lock/hidden/)
38	+	- [An experimental
39	+	version](https://jstrieb.github.io/projects/hidden-bookmarks/#demo), designed
40	+	to test the limits of the idea
41	+
42	+
43	+	# How It Works
44	+
45	+	Bookmark knocking is similar to [port
46	+	knocking](https://en.wikipedia.org/wiki/Port_knocking), for which it was named.
47	+	A user who wants access to a hidden link must know to click the right bookmarks
48	+	in the right "knock sequence." If they do this, they will be redirected to the
49	+	hidden page.
50	+
51	+	The concept relies on storing encrypted data about the hidden link in the [URL
52	+	fragment](https://en.wikipedia.org/wiki/URI_fragment) or "hash." This is the
53	+	part of the URL that comes after a `#`, and typically takes a user to some spot
54	+	in the middle of the page.
55	+
56	+	In this case, the hash contains a
57	+	[base64](https://en.wikipedia.org/wiki/Base64)-encoded
58	+	[JSON](https://en.wikipedia.org/wiki/JSON) object. The object consists of the
59	+	[AES](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard)-encrypted
60	+	secret URL and the currently-attempted knock sequence. The knock sequence
61	+	attempt is stored as a string of characters, and is used as a passphrase to
62	+	try decrypting the secret link after each knock.
63	+
64	+	When one of the special knock sequence bookmarks is clicked, it runs JavaScript
65	+	to check if the current URL fragment is base64-encoded JSON with the required
66	+	information. If not, it redirects to the user-specified decoy bookmark link. If
67	+	so, it adds some static characters to the current passphrase attempt string and
68	+	tries to decrypt the hidden link using the newly-modified passphrase.
69	+
70	+	If decryption succeeds, it redirects to the now-decrypted, no-longer-hidden
71	+	link. On the other hand, if this attempt fails, it redirects to the bookmark
72	+	link that it normally would, but with a URL fragment containing updated
73	+	information about the latest attempt. Then the user can perform the next knock
74	+	in the sequence, and the process repeats.
75	+
76	+	Since it is perfectly valid to have an arbitrary hash at the end of a typical
77	+	URL, the bookmark behaves normally if the knock sequence is incorrect or
78	+	incomplete. The only distinguishing feature of the decoy bookmark URLs is the
79	+	presence of a long, nonsensical fragment, which wouldn't alarm most people.
80	+
81	+	## Link Lock Version
82	+
83	+	The simplified version of bookmark knocking built into Link Lock only supports
84	+	two knocks. There is one universal second knock for any valid first knock. Then
85	+	the hidden link prompts for a password. This two-knock version provides a
86	+	practical level of privacy, without compromising on usability or security.
87	+
88	+
89	+	<!--
90	+	In port knocking, a user who attempts connections to closed ports is granted
91	+	access if they connect to the correct ports in the correct order. For bookmark
92	+	knocking, a user who clicks certain, otherwise-normal bookmarks in the right
93	+	order is redirected to a hidden link.
94	+	-->
95	+
96	+
97	+
98	+	# Who It Is For
99	+
100	+	Software security claims are only valid relative to a well-defined threat
101	+	model. In this case, the software aims to be secure against family and friends,
102	+	not agencies.
103	+
104	+	In other words, links protected with bookmark knocking (as implemented here)
105	+	will be difficult to notice for most people, let alone crack. But the
106	+	protection can be noticed by an astute observer, and can be broken by a
107	+	determined adversary. (The keyspace is extremely small. Assume any attacker
108	+	with all of the bookmarks in the knock sequence and the ability to brute force
109	+	AES-GCM-encrypted data will successfully uncover your hidden link. On the other
110	+	hand, if you hide a Link Lock URL, the hidden link will be securely
111	+	password-protected.)
112	+
113	+	Despite shortcomings, bookmark knocking is still a useful part of
114	+	defense-in-depth. For more serious security, use the version built into [Link
115	+	Lock](https://jstrieb.github.io/link-lock/).
116	+
117	+	**Don't forget to use private browsing or incognito mode when accessing hidden
118	+	links, otherwise the secret links are stored in your browser history, and the
119	+	protection is worthless!**
120	+
121	+	Example use cases:
122	+
123	+	- Hide private links from other users of a shared computer
124	+	- Prevent embarrassing bookmarks from being accidentally opened during a
125	+	live-stream, video call, or demonstration
126	+	- Access a secret link without typing in a password (if there is concern about
127	+	keyloggers or other [stalkerware](https://en.wikipedia.org/wiki/Stalkerware))
128	+	- Create a fun riddle or prank for the owner of a computer you gain access to
129	+	- Discreetly save personal bookmarks to a work computer
130	+
131	+
132	+
133	+	# Known Issues
134	+
135	+	If you have ideas for how to address the following problems, or want to discuss
136	+	others, please [open an issue on
137	+	GitHub](https://github.com/jstrieb/link-lock/issues/new) or use my [contact
138	+	form](https://jstrieb.github.io/about#contact).
139	+
140	+	- Generated bookmarks are prefixed with `javascript:` and therefore cannot have
141	+	favicons. As such, they're not perfectly identical to a regular bookmark for
142	+	the same site.
143	+	- Websites that modify the URL fragment will screw up the bookmark knocking.
144	+	These sites should not be used for steps in the knock sequence. Some examples
145	+	include Gmail and Telegram.
146	+	- Only tested with desktop Firefox and Chrome. Not tested with Safari, Edge, or
147	+	on mobile devices.
148	+	- Despite spending hours revising the instructions for the [Link Lock hidden
149	+	bookmarks](https://jstrieb.github.io/link-lock/hidden/) page, it is still far
150	+	from perfect. Making this idea easy to use and understand is very difficult.
151	+
152	+
153	+
154	+	# For Abuse Victims
155	+
156	+	This technology is designed to be helpful for anyone who needs more privacy
157	+	than they feel they have, but it cannot guarantee anything. You are the expert
158	+	in your own situation, and you need to judge if it is appropriate to use this
159	+	software. If you are in a dangerous situation, please seek help.
160	+
161	+	From a [New York Times
162	+	Article](https://www.nytimes.com/wirecutter/blog/domestic-abusers-can-control-your-devices-heres-how-to-fight-back/)
163	+	on technology and domestic abuse:
164	+
165	+	> If you are in immediate danger, call 911.
166	+	>
167	+	> If your calls are being tracked, call your local services hotline, like 211
168	+	> or 311, and ask to be transferred to a local resource center.
169	+	>
170	+	> If you or someone you know is in an abusive relationship or has been sexually
171	+	> assaulted, call the [National Sexual Assault
172	+	> Hotline](https://www.rainn.org/get-help/national-sexual-assault-hotline) at
173	+	> 800-656-HOPE or the [National Domestic Violence
174	+	> Hotline](https://www.thehotline.org/) at 800-799-SAFE (you can also [chat
175	+	> live with an advocate at
176	+	> NDVH](https://www.thehotline.org/what-is-live-chat/), or text LOVEIS to
177	+	> 22522).
178	+

■ ■ ■ ■ ■ ■

hidden/index.html

		skipped 47 lines
48	48		<h1>Create Hidden Bookmarks</h1>
49	49		<p>It is possible to protect bookmarks with a password using <a href="https://jstrieb.github.io/link-lock" target="_blank">Link Lock</a>, but a link that needs a password may appear suspicious to someone else seeing it. Hidden bookmarks solve this problem.</p>
50	50		<p>Hidden bookmarks are disguised to be identical to normal bookmarks, with one exception: clicking them in the right order will open a hidden link. <b>To open the hidden link, click the disguised bookmark first, and then click the decrypt bookmark next.</b> The same decrypt bookmark works for all disguised bookmarks.</p>
	51	+	<p>Read more about how hidden bookmarks work <a target="_blank" href="https://jstrieb.github.io/projects/hidden-bookmarks/">here</a>.</p>
51	52
52	53		<p>Here is how to create hidden bookmarks:</p>
53	54		<ol>
		skipped 184 lines

Link to post and add hidden-bookmarks README