diff --git a/auth.go b/auth.go
new file mode 100644
index 0000000..27a7077
--- /dev/null
+++ b/auth.go
@@ -0,0 +1,68 @@
+package main
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/shazow/ssh-chat/sshd"
+)
+
+// Auth stores fingerprint lookups
+type Auth struct {
+	whitelist map[string]struct{}
+	banned    map[string]struct{}
+	ops       map[string]struct{}
+
+	sshd.Auth
+	sync.RWMutex
+}
+
+// AllowAnonymous determines if anonymous users are permitted.
+func (a Auth) AllowAnonymous() bool {
+	a.RLock()
+	ok := len(a.whitelist) == 0
+	a.RUnlock()
+	return ok
+}
+
+// Check determines if a pubkey fingerprint is permitted.
+func (a Auth) Check(fingerprint string) (bool, error) {
+	a.RLock()
+	defer a.RUnlock()
+
+	if len(a.whitelist) > 0 {
+		// Only check whitelist if there is something in it, otherwise it's disabled.
+		_, whitelisted := a.whitelist[fingerprint]
+		if !whitelisted {
+			return false, errors.New("not whitelisted")
+		}
+	}
+
+	_, banned := a.banned[fingerprint]
+	if banned {
+		return false, errors.New("banned")
+	}
+
+	return true, nil
+}
+
+// Op will set a fingerprint as a known operator.
+func (a *Auth) Op(fingerprint string) {
+	a.Lock()
+	a.ops[fingerprint] = struct{}{}
+	a.Unlock()
+}
+
+// Whitelist will set a fingerprint as a whitelisted user.
+func (a *Auth) Whitelist(fingerprint string) {
+	a.Lock()
+	a.whitelist[fingerprint] = struct{}{}
+	a.Unlock()
+}
+
+// Ban will set a fingerprint as banned.
+func (a *Auth) Ban(fingerprint string) {
+	a.Lock()
+	a.banned[fingerprint] = struct{}{}
+	a.Unlock()
+}
diff --git a/chat/channel.go b/chat/channel.go
index b4de26e..68fee01 100644
--- a/chat/channel.go
+++ b/chat/channel.go
@@ -51,8 +51,8 @@ func (ch *Channel) SetCommands(commands Commands) {
 func (ch *Channel) Close() {
 	ch.closeOnce.Do(func() {
 		ch.closed = true
-		ch.members.Each(func(u Item) {
-			u.(*User).Close()
+		ch.members.Each(func(m Item) {
+			m.(*Member).Close()
 		})
 		ch.members.Clear()
 		close(ch.broadcast)
diff --git a/chat/command.go b/chat/command.go
index 431ecb9..66e9446 100644
--- a/chat/command.go
+++ b/chat/command.go
@@ -1,6 +1,7 @@
-// FIXME: Would be sweet if we could piggyback on a cli parser or something.
 package chat
 
+// FIXME: Would be sweet if we could piggyback on a cli parser or something.
+
 import (
 	"errors"
 	"fmt"
@@ -93,8 +94,12 @@ func (c Commands) Help(showOp bool) string {
 var defaultCommands *Commands
 
 func init() {
-	c := Commands{}
+	defaultCommands = &Commands{}
+	InitCommands(defaultCommands)
+}
 
+// InitCommands injects default commands into a Commands registry.
+func InitCommands(c *Commands) {
 	c.Add(Command{
 		Prefix: "/help",
 		Handler: func(channel *Channel, msg CommandMsg) error {
@@ -217,6 +222,4 @@ func init() {
 			return nil
 		},
 	})
-
-	defaultCommands = &c
 }
diff --git a/chat/help.go b/chat/help.go
index 9e9cd42..0ab62c6 100644
--- a/chat/help.go
+++ b/chat/help.go
@@ -17,7 +17,7 @@ type help struct {
 }
 
 // NewCommandsHelp creates a help container from a commands container.
-func NewCommandsHelp(c []*Command) *help {
+func NewCommandsHelp(c []*Command) fmt.Stringer {
 	lookup := map[string]struct{}{}
 	h := help{
 		items: []helpItem{},
diff --git a/host.go b/host.go
index c6c8de7..175ba11 100644
--- a/host.go
+++ b/host.go
@@ -14,6 +14,7 @@ import (
 type Host struct {
 	listener *sshd.SSHListener
 	channel  *chat.Channel
+	commands *chat.Commands
 
 	motd string
 	auth *Auth
@@ -26,6 +27,12 @@ func NewHost(listener *sshd.SSHListener) *Host {
 		listener: listener,
 		channel:  ch,
 	}
+
+	// Make our own commands registry instance.
+	commands := chat.Commands{}
+	chat.InitCommands(&commands)
+	ch.SetCommands(commands)
+
 	go ch.Serve()
 	return &h
 }