1 Introduction
2 ------------
3
4 MoinMessage provides a library for creating, signing, encrypting, decrypting,
5 and verifying PGP/GPG content in Python along with mechanisms for updating
6 MoinMoin Wiki instances with such content such that contributors can be
7 identified from their PGP signatures and such details used to authenticate
8 their contributions.
9
10 Configuring GPG for a Wiki
11 --------------------------
12
13 Initialise a homedir for GPG and configure it using ACL (access control list)
14 properties:
15
16 ./scripts/init_wiki_keyring.sh WIKI WEBUSER
17
18 Here, WIKI should be replaced by the top-level Wiki instance directory, and
19 WEBUSER should be the name of the user under which the Web server operates.
20
21 Note that this script may need re-running after the homedir has been changed
22 by gpg operations as gpg likes to remove permissions from various files.
23
24 To be in any way useful, signing keys must be made available within this
25 homedir so that incoming messages can have their senders verified.
26
27 To see the keys available to you in your own environment:
28
29 gpg --list-keys --with-fingerprint
30
31 The full fingerprints are used when defining a user mapping in the Wiki, and
32 the --with-fingerprint option is used to show them. Otherwise, only the last
33 eight characters of the fingerprints are shown.
34
35 Export the public key used when signing messages from your own environment:
36
37 gpg --armor --output 1C1AAF83.asc --export 1C1AAF83
38
39 Import the key into the Wiki's GPG homedir:
40
41 gpg --homedir wiki/gnupg --import 1C1AAF83.asc
42
43 For the Wiki to receive encrypted data, a key for the Wiki must be created:
44
45 gpg --homedir wiki/gnupg --gen-key
46
47 For the Wiki environment to be able to use the key, password access must be
48 disabled. This can be done by either not specifying a password or by removing
49 it later using the --edit-key option.
50
51 Export the Wiki's key for encrypting messages sent to the Wiki:
52
53 gpg --homedir wiki/gnupg --armor --output 0891463A.asc --export 0891463A
54
55 This exported key can now be imported into your own environment:
56
57 gpg --import 0891463A.asc
58
59 Configuring the Wiki
60 --------------------
61
62 In the Wiki configuration, define the following settings:
63
64 moinmessage_gpg_homedir
65 This sets the path to the homedir initialised above.
66
67 moinmessage_gpg_users_page (optional, default is MoinMessageUserDict)
68 This provides a mapping from key fingerprints to Moin usernames.
69
70 moinmessage_gpg_signing_users_page (optional, default is MoinMessageSigningUserDict)
71 This provides a mapping from Moin usernames to key fingerprints.
72
73 moinmessage_gpg_recipients_page (optional, default is MoinMessageRecipientsDict)
74 This provides a mapping from recipients to remote URLs and key fingerprints.
75
76 Fingerprints and Keys
77 ---------------------
78
79 All fingerprints mentioned in the various configuration pages must exclude
80 space characters - that is, the letters and digits must appear together in a
81 continuous block of text - and refer to keys available in the Wiki homedir.
82
83 The Fingerprint-to-Username Mapping
84 -----------------------------------
85
86 The mapping from fingerprints to usernames typically defined by the
87 MoinMessageUserDict page is a WikiDict having the following general format:
88
89 fingerprint:: username
90
91 Each fingerprint corresponds to a key used by a person wanting to send
92 messages to the Wiki to sign such messages.
93
94 Each username must correspond to a registered user in the Wiki.
95
96 The Username-to-Signing Key Mapping
97 -----------------------------------
98
99 The mapping from usernames to fingerprints typically defined by the
100 MoinMessageSigningUserDict page is a WikiDict having the following general
101 format:
102
103 username:: fingerprint
104
105 Each fingerprint corresponds to a key available in the Wiki's GPG homedir
106 generated for the purpose of signing the specified user's messages. Such a key
107 is not the same as one used by a person to send messages to the Wiki since
108 only the public key used to verify such messages should be known to the Wiki.
109
110 The Recipients Mapping
111 ----------------------
112
113 The mapping from recipients to remote URLs and fingerprints typically defined
114 by the MoinMessageRecipientsDict page is a WikiDict having the following
115 general format:
116
117 recipient:: URL fingerprint
118
119 Each URL must refer to a resource that can accept MoinMessage content.
120
121 Each fingerprint corresponds to a key used by the remote site (as identified
122 by the URL) for the decryption of messages.
123
124 Quick Start: Signing, Encrypting and Sending Messages
125 -----------------------------------------------------
126
127 To send a message signed and encrypted to a resource on localhost:
128
129 python tests/test_send.py 1C1AAF83 0891463A http://localhost/wiki/ShareTest \
130 collection update 'An update to the Wiki.' 'Another update.'
131
132 Here, the first identifier is a reference to the signing key (over which you
133 have complete control), and the second identifier is a reference to the
134 encryption key (which is a public key published for the Wiki).
135
136 This needs password protection to be removed from the secret key in the Web
137 server environment. It also uses a modified trust model when invoking gpg in
138 order to avoid complaints about the identity of the sender during encryption.
139
140 Below, the mechanisms employed are illustrated through the use of the other
141 test programs.
142
143 Signing
144 -------
145
146 Prepare a message signed with a "detached signature" (note that this does not
147 seem to be what gpg calls a detached signature with the --detach-sig option):
148
149 python tests/test_message.py collection update 'An update to the Wiki.' \
150 'Another update.' \
151 | python tests/test_sign.py 1C1AAF83
152
153 The complicated recipe based on the individual operations is as follows:
154
155 python tests/test_message.py collection update 'An update to the Wiki.' \
156 'Another update.' \
157 > test.txt \
158 && cat test.txt \
159 | gpg --armor -u 1C1AAF83 --detach-sig \
160 | python tests/test_sign_wrap.py test.txt
161
162 Encryption
163 ----------
164
165 Prepare a message with an encrypted payload using the above key:
166
167 python tests/test_message.py collection update 'An update to the Wiki.' \
168 'Another update.' \
169 | python tests/test_encrypt.py 0891463A
170
171 The complicated recipe based on the individual operations is as follows:
172
173 python tests/test_message.py collection update 'An update to the Wiki.' \
174 'Another update.' \
175 > test.txt \
176 && cat test.txt \
177 | gpg --armor -r 0891463A --encrypt --trust-model always \
178 | python tests/test_encrypt_wrap.py
179
180 Note that "--trust-model always" is used only to avoid prompting issues.
181
182 Signing and Encrypting
183 ----------------------
184
185 Sign and encrypt a message:
186
187 python tests/test_message.py collection update 'An update to the Wiki.' \
188 'Another update.' \
189 | python tests/test_sign.py 1C1AAF83 \
190 | python tests/test_encrypt.py 0891463A
191
192 The complicated recipe based on the individual operations is as follows:
193
194 python tests/test_message.py collection update 'An update to the Wiki.' \
195 'Another update.' \
196 > test.txt \
197 && cat test.txt \
198 | gpg --armor -u 1C1AAF83 --detach-sig \
199 | python tests/test_sign_wrap.py test.txt \
200 | gpg --armor -r 0891463A --encrypt --trust-model always \
201 | python tests/test_encrypt_wrap.py
202
203 Posting a Message
204 -----------------
205
206 To post a signed and/or encrypted message, output from the above activities
207 can be piped into the following command:
208
209 python tests/test_post.py http://localhost/wiki/ShareTest
210
211 Here, the resource "/wiki/ShareTest" on localhost is presented with the
212 message.
213
214 The Message Format
215 ------------------
216
217 Messages are MIME-encoded and consist of one or more update fragments. Where
218 the "Update-Type" header is present and set to a value of "collection", a
219 multipart message describes as many updates as there are parts. Otherwise,
220 only a single update is described by the message.
221
222 For each update, the "Update-Action" header indicates the action to be taken
223 with the update content. Where it is absent, the content is inserted into the
224 Wiki page specified in the request; where it is present and set to "replace",
225 the content replaces all content on the Wiki page; where it is set to "store",
226 the content is stored in a message store associated with the Wiki page.
227
228 Each update may describe multiple representations of some content by employing
229 a multipart section containing parts for each of the representations.
230 Alternatively, a single message part may describe a single representation.