Added SSL (Secure Sockets Layer) support, inspired by patch by rcaskey (issue 79). The automatic certificate creation does not work well; so the system instead instructs and gives example on how to create your own using third-party tools. I can connect to the server using a twisted-client instance, but not that many regular mud clients seem to support SSL at all (and if they do I don't know to configure them ...)

src/server/ssl.py

@@ -0,0 +1,69 @@
+"""
+This is a simple context factory for auto-creating 
+SSL keys and certificates. 
+"""
+
+import os, sys
+from twisted.internet import ssl as twisted_ssl
+try:
+    import OpenSSL
+except ImportError:
+    print "  SSL_ENABLED requires PyOpenSSL."
+    sys.exit()
+
+from src.server.telnet import TelnetProtocol
+
+class SSLProtocol(TelnetProtocol):
+    """
+    Communication is the same as telnet, except data transfer
+    is done with encryption. 
+    """
+    pass
+
+def verify_SSL_key_and_cert(keyfile, certfile):
+    """
+    This function looks for RSA key and certificate in the current
+    directory. If files ssl.key and ssl.cert does not exist, they 
+    are created.
+    """
+
+    if not (os.path.exists(keyfile) and os.path.exists(certfile)):
+        # key/cert does not exist. Create. 
+        import subprocess
+        from Crypto.PublicKey import RSA        
+        from twisted.conch.ssh.keys import Key
+
+        print "  Creating SSL key and certificate (this need only be done once)."
+
+        # create the RSA key and store it.
+        KEY_LENGTH = 1024
+        rsaKey = Key(RSA.generate(KEY_LENGTH))
+        keyString = rsaKey.toString(type="OPENSSH")    
+        file(keyfile, 'w+b').write(keyString)
+
+        # try to create the certificate
+        CERT_EXPIRE = 365 * 20 # twenty years validity        
+        # default: 
+        #openssl req -new -x509 -key ssl.key -out ssl.cert -days 7300
+        exestring = "openssl req -new -x509 -key %s -out %s -days %s" % (keyfile, certfile, CERT_EXPIRE)
+        #print "exestring:", exestring
+        try:
+            err = subprocess.call(exestring)#, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        except OSError, e:
+            print "  %s\n" % e
+            print "  Evennia's SSL context factory could not automatically create an SSL certificate game/%s." % certfile
+            print "  A private key 'ssl.key' was already created. Please create %s manually using the commands valid " % certfile
+            print "  for your operating system." 
+            print "  Example (linux, using the openssl program): "
+            print "    %s" % exestring
+            sys.exit()
+
+def getSSLContext():
+    """
+    Returns an SSL context (key and certificate). This function
+    verifies that key/cert exists before obtaining the context, and if
+    not, creates them.
+    """
+    keyfile, certfile = "ssl.key", "ssl.cert"
+    verify_SSL_key_and_cert(keyfile, certfile)
+    return twisted_ssl.DefaultOpenSSLContextFactory(keyfile, certfile)