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1 How often have we to do a key lookup by mailaddress?.
2 can this be accomplished by an external program?
6 What about using S-Exp to describe the interface to the ciphers instead
7 of simply iterating over them. This way we can easy register a name which
8 can be used as the "hintstr" for --load-extension.
10 EGD
11 ====
12 Oh, and on embedding egd into the gpg package: I think if you just unpack it
13 into, say, util/egd/* then you can put something like this into configure.in:
15 AC_CHECK_PROG(perl_present, perl, true, false)
16 if $perl_present; then
17 AC_PATH_PROG(PERL, perl)
18 (cd util/egd; $PERL Makefile.PL FULLPERL=$PERL INSTALLBIN=$sbindir)
19 fi
20 AM_CONDITIONAL(WITH_EGD, $perl_present)
22 and add util/egd to the top-level Makefile directory list inside a WITH_EGD
23 conditional.
25 * What shall we do if we have a valid subkey revocation certificate
26 but no subkey binding? Is this a valid but revoked key?
28 * use a mmaped file for secure memory if mlock does not work and
29 make sure that this file is always wiped out. Is this really
30 more secure than swapping out to the swap disk? I don't
31 believe so because if an attacker has access to the physical
32 box (and he needs this to look at the swap area) he can also
33 leave a Trojan horse which is far more easier than to analyze
34 memory dumps. Question: Is it possible that a Unix pages
35 an old (left over by some other process) swap page in for
36 another process - this should be considered a serious design
37 flow/bug.
39 Date: Mon, 4 Jan 1999 19:34:29 -0800 (PST)
40 From: Matthew Skala <mskala@ansuz.sooke.bc.ca>
42 - Signing with an expired key doesn't work by default, does work with a
43 special option.
44 - Verifying a signature that appears to have been made by an expired key
45 after its expiry date but is otherwise good reports the signature as BAD,
46 preferably with a message indicating that it's a key-expiry problem rather
47 than a cryptographically bad signature.
48 - Verifying a signature from a key that is now expired, where the
49 signature was made before the expiry date, reports the signature as
50 GOOD, possibly with a warning that the key has since expired.
51 - Encrypting to an expired key doesn't work by default, does work with a
52 special option.
53 - Decrypting always works, if you have the appropriate secret key and
54 passphrase.
58 ==============================
59 [ "-->" indicates a comment by me (wk) ]
61 Hi Werner..
63 I was looking at some of the PROJECTS items in the recent gpg CVS and wanted
64 to comment on one of them:
66 * Add a way to override the current cipher/md implementations
67 by others (using extensions)
69 As you know I've been thinking about how to use a PalmPilot or an iButton in
70 some useful way in GPG. The two things that seem reasonable are:
71 1) keep the secret key in the device, only transferring it to the host
72 computer for the duration of the secret-key operation (sign or decrypt).
73 The key is never kept on disk, only in RAM. This removes the chance that
74 casual snooping on your office workstation will reveal your key (it
75 doesn't help against an active attack, but the attacker must leave a
76 tampered version of GPG around or otherwise get their code to run while
77 the key-storage device is attached to attack the key)
78 2) perform the secret-key operation on the device, so the secret key never
79 leaves the confines of that device. There are still attacks possible,
80 based upon talking to the device while it is connected and trying to
81 convince the device (and possibly the user) that it is the real GPG,
82 but in general this protects the key pretty strongly. Any individual
83 message is still vulnerable, but that's a tradeoff of the convenience of
84 composing that message on a full-sized screen+keyboard (plus the added
85 speed of encryption) vs. the security of writing the message on a
86 secure device.
88 I think there are a variety of ways of implementing these things, but a few
89 extension mechanisms in GPG should be enough to try various ways later on.
91 1) pass an argument string to loadable extension modules (maybe
92 gpg --load-extension foofish=arg1,arg2,arg3 ?)
93 --> could also be achived by S-Exps
95 2) allow multiple instances of the same extension module (presumably with
96 different arguments)
97 --> set an alias name when loading them
98 3) allow extension modules to use stdin/stdout/stderr as normal (probably
99 already in there), for giving feedback to the user, or possibly asking them
100 for a password of some sort
101 --> there should really be some kind of callback mechanism.
103 4) have an extension to provide secret keys:
105 It looks like most of the hooks for this are already in place, it just
106 needs an extension module which can register itself as a keyblock resource.
108 I'm thinking of a module for this that is given an external program name as
109 an argument. When the keyblock resource is asked to enumerate its keys, it
110 runs the external program (first with a "0" argument, then a "1", and so on
111 until the program reports that no more keys are available). The external
112 --> better use a cookie: This way we are also stateless but have a more
113 general interface.
115 program returns one (possibly armored) secret key block each time. The
116 program might have some kind of special protocol to talk to the storage
117 device. One thing that comes to mind is to simply include a random number
118 in the message sent over the serial port: the program would display this
119 number, the Pilot at the other end would display the number it receives, if
120 the user sees that both are the same they instruct the Pilot to release the
121 key, as basic protection against someone else asking for the key while it
122 is attached. More sophisticated schemes are possible depending upon how
123 much processing power and IO is available on the device. But the same
124 extension module should be able to handle as complex a scheme as one could
125 wish.
126 --> authenticate the session on startup, using DH and the mentioned
127 cookie/screen/keyboard authentication.
129 The current keyblock-resource interface would work fine, although it
130 might be more convenient if a resource could be asked for a key by id
131 instead of enumerating all of them and then searching through the resulting
132 list for a match. A module that provided public keys would have to work this
133 way (imagine a module that could automatically do an http fetch for a
134 particular key.. easily-added automatic key fetching). Without that ability
135 to fetch by id (which would require it to fall back to the other keyblock
136 resources if it failed), the user's device might be asked to release the
137 key even though some other secret key was the one needed.
138 --> Right.
141 5) have an extension to perform a secret-key operation without the actual
142 secret key material
143 --> Define a clear interface to do this and in the first step write
144 a daemon which does exactly this.
146 basically something to indicate that any decrypt or sign operations that
147 occur for a specific keyid should call the extension module instead. The
148 secret key would not be extracted (it wouldn't be available anyway). The
149 module is given the keyid and the MPI of the block it is supposed to sign
150 or decrypt.
152 The module could then run an external program to do the operation. I'm
153 imagining a Pilot program which receives the data, asks the user if it can go
154 along with the operation (after displaying a hash of the request, which is
155 also displayed by the extension module's program to make sure the Pilot is
156 being asked to do the right operation), performs the signature or decryption,
157 then returns the data. This protocol could be made arbitrarily complex, with
158 a D-H key to encrypt the link, and both sides signing requests to
159 authenticate one to the other (although this transforms the the problem of
160 getting your secret key off your office workstation into the problem of
161 your workstation holding a key tells your Pilot that it is allowed to perform
162 the secret key operation, and if someone gets a hold of that key they may
163 be able to trick your pilot [plugged in somewhere else] to do the same thing
164 for them).
166 This is basically red/black separation, with the Pilot or iButton having the
167 perimeter beyond which the red data doesn't pass. Better than the secret-key
168 storage device but requires a lot more power on the device (the new iButtons
169 with the exponentiator could do it, but it would take way too much code space
170 on the old ones, although they would be fine for just carrying the keys).
172 The signature code might need to be extended to verify the signature you just
173 made, since an active intruder pretending to the the Pilot wouldn't be able to
174 make a valid signature (but they might sign your message with a different key
175 just to be annoying).
177 Anyway, just wanted to share my thoughts on some possibilities. I've been
178 carrying this little Java iButton on my keyring for months now, looking for
179 something cool to do with it, and I think that secure storage for my GPG key
180 would be just the right application.
182 cheers,
183 -Brian
185 -----BEGIN PGP SIGNATURE-----
186 Version: GnuPG v0.4.5 (GNU/Linux)
187 Comment: For info finger gcrypt@ftp.guug.de
189 iD8DBQE2c5oZkDmgv9E5zEwRArAwAKDWV5fpTtbGPiMPgl2Bpp0gvhbfQgCgzJuY
190 AmIQTk4s62/y2zMAHDdOzK0=
191 =jr7m
192 -----END PGP SIGNATURE-----
196 About a new Keyserver (discussion with Allan Clark <allanc@sco.com>):
197 =====================
199 Some ideas:
201 o the KS should verify signatures and only accept those
202 which are good.
204 o Keep a blacklist of known bad signatures to minimize
205 the time needed to check them
207 o Should be fast - I'm currently designing a new storage
208 system called keybox which takes advantage of the fact
209 that the keyID is highly random and can directly be
210 used as a hash value and this keyID is (for v4 keys)
211 part of the fingerprint: So it is possible to use the
212 fingerprint as key but do an lookup by the keyID.
214 o To be used as the "public keyring" in a LAN so that there
215 is no need to keep one on every machine.
217 o Allow more that one file for key storage.
219 o Use the HKS protocol and enhance it in a way that binary
220 keyrings can be transmitted. (I already wrote some
221 http server and client code which can be used for this)
222 And extend it to allow reuse of a connection.
224 o Keep a checksum (hash) of the entire keyblock so that a
225 client can easy check whether this keyblock has changed.
226 (keyblock = the entire key with all certificates etc.)
227 Transmitted in the HEAD info.
229 o Allow efficient propagation of new keys and revocation
230 certificates.
233 Probably more things but this keyserver is not a goal for the
234 1.0 release. Someone should be able to fix some of the limitations
235 of the existing key servers (I think they bail out on some rfc2440
236 packet formats).
239 DJGPP
240 =====
241 Don't use symlinks but try to do the preprocessing in the config-links script.
242 DJPGG has problems to distinguish betwen .s and .S becaus the FAT filesystem
243 is not case sensitive (Mark Elbrecht).
244 Well, it runs only on one architecture and therefor it might be possible
245 to add a special case for it, completely bypassing the symlink autselection
246 trick.
248 Special procmail addresses
249 ==========================
250 * foo+bar@example.net: Try to match the address without the "+bar".
251 Should be done by the MUA, but maybe we can do this.
252 --> Yep. Another reason to utilize a directory service or something
253 else for keylookup.
257 Suggested things which I will not do:
258 =====================================
259 * Let take --help an option to select some topics.
260 Using grep is much easier
261 * Check if an object (a message, detached sign, public key, or whatever)
262 is signed by definite user, i.e. define user
263 (userid, or any other unique identification) on command line.
264 --> Use a script and --status-fd
267 Copyright 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
269 This file is free software; as a special exception the author gives
270 unlimited permission to copy and/or distribute it, with or without
271 modifications, as long as this notice is preserved.
273 This file is distributed in the hope that it will be useful, but
274 WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
275 implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.