diff --git a/bfxapi/client.py b/bfxapi/client.py
index 7374251..cefd5ce 100644
--- a/bfxapi/client.py
+++ b/bfxapi/client.py
@@ -7,5 +7,5 @@ class Constants(str, Enum):
     PUB_WSS_HOST = "wss://api-pub.bitfinex.com/ws/2"
 
 class Client(object):
-    def __init__(self, WSS_HOST: str = Constants.WSS_HOST):
-        self.wss = BfxWebsocketClient(host=WSS_HOST)
\ No newline at end of file
+    def __init__(self, WSS_HOST: str = Constants.WSS_HOST, API_KEY: str = None, API_SECRET: str = None):
+        self.wss = BfxWebsocketClient(host=WSS_HOST, API_KEY=API_KEY, API_SECRET=API_SECRET)
\ No newline at end of file
diff --git a/bfxapi/websocket/BfxWebsocketClient.py b/bfxapi/websocket/BfxWebsocketClient.py
index dad9ec1..3b8ee70 100644
--- a/bfxapi/websocket/BfxWebsocketClient.py
+++ b/bfxapi/websocket/BfxWebsocketClient.py
@@ -1,30 +1,31 @@
-import json, asyncio, websockets
+import json, asyncio, hmac, hashlib, time, websockets
 
 from pyee.asyncio import AsyncIOEventEmitter
 
 from .manager import Manager
-from .channels import Channels
-from .errors import ConnectionNotOpen
+
+from .errors import ConnectionNotOpen, AuthenticationCredentialsError
 
 class BfxWebsocketClient(object):
-    def __init__(self, host, channels=None):
+    def __init__(self, host, API_KEY=None, API_SECRET=None):
         self.host, self.chanIds, self.event_emitter = host, dict(), AsyncIOEventEmitter()
 
         self.manager, self.websocket = Manager(event_emitter=self.event_emitter), None
 
-        self.channels = channels or list()
+        self.API_KEY, self.API_SECRET = API_KEY, API_SECRET
 
     def run_forever(self):
         asyncio.run(self.connect())
 
     async def connect(self):
         async for websocket in websockets.connect(self.host):
-            try:
-                self.websocket = websocket
+            self.websocket = websocket
 
-                for channel, parameters in self.channels:
-                    await self.subscribe(channel, **parameters)
-                else: self.event_emitter.emit("open")
+            try:     
+                self.event_emitter.emit("open")
+
+                if self.API_KEY != None and self.API_SECRET != None:
+                    self.authenticate(self.API_KEY, self.API_SECRET)
 
                 async for message in websocket:
                     message = json.loads(message)
@@ -38,12 +39,21 @@ class BfxWebsocketClient(object):
                         if message["status"] == "OK":
                             del self.chanIds[message["chanId"]]
 
+                    elif isinstance(message, dict) and message["event"] == "auth":
+                        if message["status"] == "OK":
+                            self.chanIds[message["chanId"]] = message
+
+                            self.event_emitter.emit("authenticated", message)
+                        else: raise AuthenticationCredentialsError("Cannot authenticate with given API-KEY and API-SECRET.")
+
                     elif isinstance(message, list):
                         chanId, parameters = message[0], message[1:]
+                        
                         self.manager.handle(self.chanIds[chanId], *parameters)
             except websockets.ConnectionClosed:
                 continue
         
+    @staticmethod
     def __require_websocket_connection(function):
         async def wrapper(self, *args, **kwargs):
             if self.websocket == None or self.websocket.open == False:
@@ -68,6 +78,22 @@ class BfxWebsocketClient(object):
             "chanId": chanId
         }))
 
+    @__require_websocket_connection
+    async def authenticate(self, API_KEY, API_SECRET, filter=None):
+        data = { "event": "auth", "filter": filter, "apiKey": API_KEY }
+
+        data["authNonce"] = int(time.time()) * 1000
+
+        data["authPayload"] = "AUTH" + str(data["authNonce"])
+
+        data["authSig"] = hmac.new(
+            API_SECRET.encode("utf8"),
+            data["authPayload"].encode("utf8"),
+            hashlib.sha384 
+        ).hexdigest()
+
+        await self.websocket.send(json.dumps(data))
+
     async def clear(self):
         for chanId in self.chanIds.keys():
             await self.unsubscribe(chanId)
@@ -76,4 +102,10 @@ class BfxWebsocketClient(object):
         def handler(function):
             self.event_emitter.on(event, function)
 
+        return handler 
+
+    def once(self, event):
+        def handler(function):
+            self.event_emitter.once(event, function)
+
         return handler 
\ No newline at end of file
diff --git a/bfxapi/websocket/errors.py b/bfxapi/websocket/errors.py
index d049ac7..693dbe3 100644
--- a/bfxapi/websocket/errors.py
+++ b/bfxapi/websocket/errors.py
@@ -1,7 +1,13 @@
 class ConnectionNotOpen(Exception):
     """
     This error indicates an attempt to communicate via websocket before starting the connection with the servers.
-    
+    """
+
+    pass
+
+class AuthenticationCredentialsError(Exception):
+    """
+    This error indicates that the user has provided incorrect credentials (API-KEY and API-SECRET) for authentication.
     """
 
     pass
\ No newline at end of file