diff --git a/demo.py b/demo.py
index b85fc01..d0dda7f 100755
--- a/demo.py
+++ b/demo.py
@@ -24,32 +24,6 @@ import paramiko
 
 #####   utility functions
 
-def load_host_keys():
-    # this file won't exist on windows, but windows doesn't have a standard
-    # location for this file anyway.
-    filename = os.path.expanduser('~/.ssh/known_hosts')
-    keys = {}
-    try:
-        f = open(filename, 'r')
-    except Exception, e:
-        print '*** Unable to open host keys file (%s)' % filename
-        return
-    for line in f:
-        keylist = line.split(' ')
-        if len(keylist) != 3:
-            continue
-        hostlist, keytype, key = keylist
-        hosts = hostlist.split(',')
-        for host in hosts:
-            if not keys.has_key(host):
-                keys[host] = {}
-            if keytype == 'ssh-rsa':
-                keys[host][keytype] = paramiko.RSAKey(data=base64.decodestring(key))
-            elif keytype == 'ssh-dss':
-                keys[host][keytype] = paramiko.DSSKey(data=base64.decodestring(key))
-    f.close()
-    return keys
-
 def agent_auth(username, t, event):
     agent = paramiko.Agent()
     agent_keys = agent.get_keys()
@@ -137,7 +111,12 @@ try:
         sys.exit(1)
     # print repr(t)
 
-    keys = load_host_keys()
+    try:
+        keys = paramiko.util.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))
+    except IOError:
+        print '*** Unable to open host keys file'
+        keys = {}
+
     key = t.get_remote_server_key()
     if not keys.has_key(hostname):
         print '*** WARNING: Unknown host key!'
diff --git a/paramiko/__init__.py b/paramiko/__init__.py
index 6224f4f..d13477d 100644
--- a/paramiko/__init__.py
+++ b/paramiko/__init__.py
@@ -65,7 +65,7 @@ __license__ = "GNU Lesser General Public License (LGPL)"
 
 
 import transport, auth_transport, channel, rsakey, dsskey, message
-import ssh_exception, file, packet, agent, server
+import ssh_exception, file, packet, agent, server, util
 import sftp_client, sftp_attr, sftp_handle, sftp_server, sftp_si
 
 randpool = transport.randpool
@@ -126,6 +126,7 @@ __all__ = [ 'Transport',
             'pkey',
             'message',
             'ssh_exception',
+            'sftp',
             'sftp_client',
             'sftp_server',
             'sftp_attr',
diff --git a/paramiko/util.py b/paramiko/util.py
index 1b620b8..163fb03 100644
--- a/paramiko/util.py
+++ b/paramiko/util.py
@@ -172,6 +172,46 @@ def generate_key_bytes(hashclass, salt, key, nbytes):
         nbytes -= size
     return keydata
 
+def load_host_keys(filename):
+    """
+    Read a file of known SSH host keys, in the format used by openssh, and
+    return a compound dict of C{hostname -> keytype ->} L{PKey}.  The hostname
+    may be an IP address or DNS name.  The keytype will be either C{"ssh-rsa"}
+    or C{"ssh-dss"}.
+    
+    This type of file unfortunately doesn't exist on Windows, but on posix,
+    it will usually be stored in C{os.path.expanduser("~/.ssh/known_hosts")}.
+    
+    @param filename: name of the file to read host keys from
+    @type filename: str
+    @return: dict of host keys, indexed by hostname and then keytype
+    @rtype: dict(hostname, dict(keytype, L{PKey}))
+    """
+    import base64
+    from rsakey import RSAKey
+    from dsskey import DSSKey
+    
+    keys = {}
+    f = file(filename, 'r')
+    for line in f:
+        line = line.strip()
+        if (len(line) == 0) or (line[0] == '#'):
+            continue
+        keylist = line.split(' ')
+        if len(keylist) != 3:
+            continue
+        hostlist, keytype, key = keylist
+        hosts = hostlist.split(',')
+        for host in hosts:
+            if not keys.has_key(host):
+                keys[host] = {}
+            if keytype == 'ssh-rsa':
+                keys[host][keytype] = RSAKey(data=base64.decodestring(key))
+            elif keytype == 'ssh-dss':
+                keys[host][keytype] = DSSKey(data=base64.decodestring(key))
+    f.close()
+    return keys
+
 def mod_inverse(x, m):
     # it's crazy how small python can make this function.
     u1, u2, u3 = 1, 0, m