1 <b>Frequently Asked Questions</b><br /><br />
3 <a href="#f1_0">1. General Questions</a><br />
4 <a href="#f1_1">1.1 What is SILC?</a><br />
5 <a href="#f1_20">1.2 When was SILC Project started?</a><br />
6 <a href="#f1_30">1.3 Why SILC in the first place?</a><br />
7 <a href="#f1_40">1.4 What license covers the SILC release?</a><br />
8 <a href="#f1_50">1.5 Why SILC? Why not IRC3?</a><br />
9 <a href="#f1_55">1.6 What platforms SILC supports?</a><br />
10 <a href="#f1_60">1.7 Where can I find more information?</a><br />
11 <a href="#f1_70">1.8 I would like to help out, what can I do?</a><br />
13 <a href="#f2_0">2. Protocol Questions</a><br />
14 <a href="#f2_10">2.1 What is the status of SILC protocol in the IETF?</a><br />
15 <a href="#f2_20">2.2 How much the SILC protocol is based on IRC?</a><br />
16 <a href="#f2_30">2.3 Why use SILC? Why not IRC with SSL?</a><br />
17 <a href="#f2_40">2.4 Can I talk from SILC network to IRC network?</a><br />
18 <a href="#f2_45">2.5 Does SILC support file transfer?</a><br />
19 <a href="#f2_47">2.6 I am behind a firewall, can I use SILC?</a><br />
20 <a href="#f2_50">2.7 How secure SILC really is?</a><br />
21 <a href="#f2_60">2.8 Does SILC support instant messaging?</a><br />
22 <a href="#f2_80">2.9 I have suggestions to SILC Protocol, what can I do?</a><br />
24 <a href="#f3_0">3. Client Questions</a><br />
25 <a href="#f3_10">3.1 Where can I find SILC clients?</a><br />
26 <a href="#f3_20">3.2 Can I use SILC with IRC client and vice versa?</a><br />
28 <a href="#f4_0">4. Server Questions</a><br />
29 <a href="#f4_10">4.1 Where can I find SILC servers?</a><br />
30 <a href="#f4_20">4.2 Can I run own SILC server?</a><br />
31 <a href="#f4_30">4.3 What is the difference between SILC server and SILC router?</a><br />
33 <a href="#f5_0">5. Toolkit Questions</a><br />
34 <a href="#f5_10">5.1 What is SILC Toolkit?</a><br />
38 <b>1. General Questions</b><br /><br />
41 <font color="#2f486f">Q: What is SILC?</font><br />
42 A: SILC (Secure Internet Live Conferencing) is a protocol which provides
43 secure conferencing services in the Internet over insecure channel. SILC
44 is IRC like although internally they are very different. Biggest
45 similarity between SILC and IRC is that they both provide conferencing
46 services and that SILC has almost same commands as IRC. Other than that
47 they are nothing alike.
49 Biggest differences are that SILC is secure what IRC is not in any way.
50 The network model is also entirely different compared to IRC.
54 <font color="#2f486f">Q: When was SILC Project started?</font><br />
55 A: The SILC development started in 1996 and early 1997. But, for various
56 reasons it suspended many times until it finally got some wind under its
57 wings in 1999. First public release was in summer 2000.
61 <font color="#2f486f">Q: Why SILC in the first place?</font><br />
62 A: Simply for fun, nothing more. And actually for need back in the days
63 when it was started. When SILC was first developed there really did not
64 exist anything like this. SILC has been very interesting and educational
69 <font color="#2f486f">Q: What license covers the SILC release?</font><br />
70 A: The SILC software developed here at silcnet.org, the SILC Client, the
71 SILC Server and the SILC Toolkit are covered by the GNU General Public
76 <font color="#2f486f">Q: Why SILC? Why not IRC3?</font><br />
77 A: Question that is justified no doubt of that. SILC was not started to
78 become a replacement for IRC. SILC was something that didn't exist in 1996
79 or even today except that SILC is now released. However, I did check out
80 the IRC3 project in 1997 when I started coding and planning the SILC protocol.
82 But, IRC3 is problematic. Why? Because it still doesn't exist. The
83 project is almost at the same spot where it was in 1997 when I checked it
84 out. And it was old project back then as well. That's the problem of IRC3
85 project. The same almost happened to SILC as well as I wasn't making real
86 progress over the years. I talked to the original author of IRC, Jarkko
87 Oikarinen, in 1997 and he directed me to the IRC3 project, although he
88 said that IRC3 is a lot of talking and not that much of anything else. I
89 am not trying to put down the IRC3 project but its problem is that no one
90 in the project is able to make a decision what is the best way to go about
91 making the IRC3 and I wasn't going to be part of that. The fact is that
92 if I would've gone to IRC3 project, nor IRC3 or SILC would exist today. I
93 think IRC3 could be something really great if they just would get their
94 act together and start coding the thing.
98 <font color="#2f486f">Q: What platforms SILC supports?</font><br />
99 A: The SILC Client is available on various Unix systems and is reported to
100 work under cygwin on Windows. The SILC Server also works on various Unix
101 systems. However, the server has not been tested under cygwin as far as we
102 know. The SILC Toolkit is distributed for all platforms, Unix, Cygwin
107 <font color="#2f486f">Q: Where can I find more information?</font><br />
108 A: For more technical information we suggest reading the SILC Protocol
109 specifications. You might also want to take a look at the <a
110 href="?page=docs">documentation </a> page on the web page.
114 <font color="#2f486f">Q: I would like to help out, what can I do?</font><br />
115 A: You might want to take a look at the <a
116 href="?page=contribute">Contributing</a> page and the <a
117 href="?page=todo">TODO</a> list. You might also want to join the
118 SILC development mailing list.
122 <b>2. Protocol Questions</b><br /><br />
125 <font color="#2f486f">Q: What is the status of SILC protocol in the IETF?</font><br />
126 A: The SILC protocol specifications has been submitted currently as
127 individual submissions. There does not currently exist a working group
128 for this sort of project. Our goal is to fully standardize the SILC and
129 thus submit it as RFC to the <a href="http://www.ietf.org/">IETF</a> at a
134 <font color="#2f486f">Q: How much SILC Protocol is based on IRC?</font><br />
135 A: SILC is not based on IRC. The client superficially resembles IRC
136 client but everything that happens under the hood is nothing alike IRC.
137 SILC could *never* support IRC because the entire network toppology is
138 different (hopefully more scalable and powerful). So no, SILC protocol
139 (client or server) is not based on IRC. Instead, We've taken good things
140 from IRC and left all the bad things behind and not even tried to burden
141 the SILC with the IRCs problems that will burden IRC and future IRC
142 projects till the end. SILC client resembles IRC client because it is
143 easier for new users to start using SILC when they already know all the
148 <font color="#2f486f">Q: Why use SILC? Why not IRC with SSL?</font><br />
149 A: Sure, that is possible, although, does that secure the entire IRC
150 network? And does that increase or decrease the lags and splits in the
151 IRC network? Does that provide user based security where some specific
152 private message are secured? Does that provide security where some
153 specific channel messages are secured? And I know, you can answer yes to
154 some of these questions. But, security is not just about applying
155 encryption to traffic and SILC is not just about `encrypting the
156 traffic`. You cannot make insecure protocol suddenly secure just by
157 encrypting the traffic. SILC is not meant to be IRC replacement. IRC is
158 good for some things, SILC is good for same and some other things.
162 <font color="#2f486f">Q: Can I talk from SILC network to IRC network?</font><br />
163 A: Simple answer for this is No. The protocols are not compatible which
164 makes it impossible to directly talk from SILC network to IRC network or
165 vice versa. Developing a gateway between these two networks would
166 technically be possible but from security point of view strongly not
167 recommended. We have no plans for developing such a gateway.
171 <font color="#2f486f">Q: Does SILC support file transfer?</font><br />
172 A: Not yet. This is a feature that will be added to the SILC protocol.
173 The exact file transfer protocol is undefined.
177 <font color="#2f486f">Q: I am behind a firewall, can I use SILC?</font><br />
178 A: Yes. If your network administrator can open the port 706 (TCP) you can
179 use SILC without problems. You may also compile your SILC client with
180 SOCKS support which will proxy your SILC session through the firewall.
184 <font color="#2f486f">Q: How secure SILC really is?</font><br />
185 A: A good question which I don't have an answer for. We have tried to make
186 SILC as secure as possible. However, there is no security protocol or
187 security software that has not been vulnerable to some sort of attacks.
188 SILC is in no means different from this. So, it is suspected that there
189 are security holes in the SILC. These holes just need to be found so
190 that they can be fixed.
192 But to give you some parameters of security SILC uses the most secure
193 crytographic algorithms such as AES(Rijndael), Twofish, Blowfish, RC5,
194 etc. SILC does not have DES or 3DES as DES is insecure and 3DES is just
195 too slow. SILC also uses cryptographically strong random number generator
196 when it needs random numbers. Public key cryptography uses RSA (PKCS #1)
197 and Diffie-Hellman algorithms. Key lengths for ciphers are initially set
198 to 256. For public key algorithms the starting key length is 1024 bits.
200 But the best answer for this question is that SILC is as secure as its
201 weakest link. SILC is open and the protocol is open and in public thus
202 open for security analysis.
204 To give a list of attacks that are ineffective against SILC:
206 - Man-in-the-middle attacks are ineffective if proper public key
207 infrastructure is used. SILC is vulnerable to this attack if the public
208 keys used in the SILC are not verified to be trusted (as any other
209 protocol for that matter).<br />
210 - IP spoofing is ineffective (because of encryption and trusted keys).<br />
211 - Attacks that change the contents of the data or add extra data to the
212 packets are ineffective (because of encryption and integrity checks).<br />
213 - Passive attacks (listenning network traffic) are ineffective (because
214 of encryption). Everything is encrypted including authentication data
215 such as passwords when they are needed.<br />
216 - Any sort of cryptanalytic attacks are tried to make ineffective by
217 using the best cryptographic algorithms out there.
221 <font color="#2f486f">Q: Does SILC support instant messaing?</font><br />
222 A: SILC is not an instant message (IM) system, like ICQ and the others.
223 SILC is more IRC like system, "real-time" chat and that kind of
228 <font color="#2f486f">Q: I have suggestions to SILC Protocol,
229 what can I do?</font><br />
230 A: All suggestions and improvements are of course welcome. You should read
231 the protocol specifications first to check out whether your idea is
232 covered by them already. The best place to make your idea public is the
233 SILC development mailing list.
237 <b>3. Client Questions</b><br /><br />
240 <font color="#2f486f">Q: Where can I find SILC clients?</font><br />
241 A: The SILC client is available for free download from the silcnet.org web
242 page. Some people have also mentioned words Java and Perl when talking
243 about SILC clients. Nothing has appeared yet, though.
247 <font color="#2f486f">Q: Can I use SILC with IRC client and vice versa?</font><br />
248 A: Generally the answer would be no for both. However, there exist already
249 at least one IRC client that supports SILC, the <a
250 href="http://irssi.org/">Irssi client</a>. The current SILC client is
251 actually based on the user interface of the Irssi client. So, yes it is
252 possible to use SILC with some IRC clients and vice versa. But, this
253 does not mean that you can talk from SILC network to IRC network, that is
258 <b>4. Server Questions</b><br /><br />
261 <font color="#2f486f">Q: Where can I find SILC servers?</font><br />
262 A: The SILC server is available for free download from the silcnet.org
263 web page. We are not aware of any other SILC server implementations, so far.
267 <font color="#2f486f">Q: Can I run own SILC server?</font><br />
268 A: Yes of course. Download the SILC server package, compile and install
269 it. Be sure to check out the installation instructions and the README
270 file. You also should decide whether you want to run SILC server or SILC
275 <font color="#2f486f">Q: What is the difference between SILC
276 server and SILC router?</font><br />
277 A: The topology of the SILC network includes SILC routers and the SILC
278 servers (and SILC clients of course). Normal SILC server does not have
279 direct connections with other SILC servers. They connect directly to the
280 SILC router. SILC Routers may have several server connections and they
281 may connect to several SILC routers. The SILC routers are the servers in
282 the network that know everything about everything. The SILC servers know
283 only local information and query global information from the router when
286 If you are running SILC server you want to run it as router only if you
287 want to have server connections in it and are prepared to accept server
288 connections. You also need to get the router connected to some other
289 router to be able to join the SILC network. You may run the server as
290 normal SILC server if you do not want to accept other server connections
291 or cannot run it as router.
295 <b>5. Toolkit Questions</b><br /><br />
298 <font color="#2f486f">Q: What is SILC Toolkit?</font><br />
299 A: SILC Toolkit is a package intended for software developers who would
300 like to develope their own SILC based applications or help in the
301 development of the SILC. The Toolkit includes SILC Protocol Core library,
302 SILC Crypto library, SILC Key Exchange (SKE) library, SILC Math
303 library, SILC Modules (SIM) library, SILC Utility library, SILC Client
304 library and few other libraries.