Added README

README.txt

@@ -0,0 +1,52 @@
+Here is a very simple chat application in which parties have to take turns.
+
+The tool has three parts:
+  keygen, the key generation tool
+  server, the listener
+  client, the connector
+
+BUILDING
+
+All three components depend on libgmp and certain POSIX APIs.
+server can be built from server.c, aes.c, comm.c, and randsource.c.
+client can be built from client.c, aes.c, comm.c, and randsource.c.
+keygen requires pthreads, and can be built from keygen.c, sgprime.c, and randsource.c.
+
+RUNNING
+
+In the current implementation, randsource.c depends on the existence of
+/dev/urandom. If there is a different source of entropy on your system, use it
+instead by changing randsource.c.
+
+keygen <bits> <output file> [threads]
+will create a <bits>-bit key and store it in <output file>. If [threads] is
+specified, that many threads will be used for the computation; otherwise just
+one will be used.
+
+client <connect address> <port>
+will connect to a given address on a given port and begin encrypted
+communication.
+
+server <key file> <bind address> <port>
+will bind a listener on the given address and port, and use the given key file
+to exchange keys upon a client connecting.
+
+CAVEATS
+
+Communication is entirely turn-based. This is to simplify the code and prevent
+inconvenience on a dumb terminal.
+
+There are probably a handful of memory errors; for example, providing a key
+shorter than an AES block size uses uninitialized memory.
+
+The AES implementation is not rigorously tested, and thus may not be
+completely conformant. Also, no inverse was ever implemented, so it uses a
+strange encryption mode.
+
+In addition to network sockets, UNIX file sockets are also supported. Instead
+of a network address, use a string of the form unix:/path/to/socket to use a
+UNIX file socket.
+
+Due to the poor specification of certain parts of POSIX involving sockets,
+it's possible that this program won't work outside of Linux.
+

client.c

@@ -13,7 +13,7 @@ int main(int argc, char **argv)
 
   if (argc != 3)
   {
-    printf("Usage: %s <bind address> <port>\n", argv[0]);
+    printf("Usage: %s <connect address> <port>\n", argv[0]);
     return 0;
   }