diff --git a/RNS/Link.py b/RNS/Link.py
index 864840e..3212313 100644
--- a/RNS/Link.py
+++ b/RNS/Link.py
@@ -100,39 +100,68 @@ class Link:
     and will be torn down.
     """
 
-    PENDING   = 0x00
-    HANDSHAKE = 0x01
-    ACTIVE    = 0x02
-    STALE     = 0x03
-    CLOSED    = 0x04
+    PENDING             = 0x00
+    HANDSHAKE           = 0x01
+    ACTIVE              = 0x02
+    STALE               = 0x03
+    CLOSED              = 0x04
 
-    TIMEOUT            = 0x01
-    INITIATOR_CLOSED   = 0x02
-    DESTINATION_CLOSED = 0x03
+    TIMEOUT             = 0x01
+    INITIATOR_CLOSED    = 0x02
+    DESTINATION_CLOSED  = 0x03
 
-    ACCEPT_NONE = 0x00
-    ACCEPT_APP  = 0x01
-    ACCEPT_ALL  = 0x02
+    ACCEPT_NONE         = 0x00
+    ACCEPT_APP          = 0x01
+    ACCEPT_ALL          = 0x02
     resource_strategies = [ACCEPT_NONE, ACCEPT_APP, ACCEPT_ALL]
 
+    MODE_AES128_CBC     = 0x00
+    MODE_AES256_CBC     = 0x01
+    MODE_AES256_GCM     = 0x02
+    MODE_OTP_RESERVED   = 0x03
+    MODE_PQ_RESERVED_1  = 0x04
+    MODE_PQ_RESERVED_2  = 0x05
+    MODE_PQ_RESERVED_3  = 0x06
+    MODE_PQ_RESERVED_4  = 0x07
+    enabled_modes       = [MODE_AES128_CBC]
+
+    MTU_BYTEMASK        = 0x1FFFFF
+    MODE_BYTEMASK       = 0xE0
+
     @staticmethod
     def mtu_bytes(mtu):
-        return struct.pack(">I", mtu & 0xFFFFFF)[1:]
+        return struct.pack(">I", mtu & Link.MTU_BYTEMASK)[1:]
 
     @staticmethod
     def mtu_from_lr_packet(packet):
         if len(packet.data) == Link.ECPUBSIZE+Link.LINK_MTU_SIZE:
-            return (packet.data[Link.ECPUBSIZE] << 16) + (packet.data[Link.ECPUBSIZE+1] << 8) + (packet.data[Link.ECPUBSIZE+2])
-        else:
-            return None
+            return (packet.data[Link.ECPUBSIZE] << 16) + (packet.data[Link.ECPUBSIZE+1] << 8) + (packet.data[Link.ECPUBSIZE+2]) & Link.MTU_BYTEMASK
+        else: return None
 
     @staticmethod
     def mtu_from_lp_packet(packet):
         if len(packet.data) == RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2+Link.LINK_MTU_SIZE:
             mtu_bytes = packet.data[RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2:RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2+Link.LINK_MTU_SIZE]
-            return (mtu_bytes[0] << 16) + (mtu_bytes[1] << 8) + (mtu_bytes[2])
-        else:
-            return None
+            return (mtu_bytes[0] << 16) + (mtu_bytes[1] << 8) + (mtu_bytes[2]) & Link.MTU_BYTEMASK
+        else: return None
+
+    @staticmethod
+    def mode_byte(mode):
+        if mode in Link.enabled_modes: return (mode << 5) & Link.MODE_BYTEMASK
+        else: raise TypeError(f"Requested link mode {mode} not enabled")
+
+    @staticmethod
+    def mode_from_lr_packet(packet):
+        if len(packet.data) > Link.ECPUBSIZE:
+            return (packet.data[Link.ECPUBSIZE] << 16) + (packet.data[Link.ECPUBSIZE+1] << 8) + (packet.data[Link.ECPUBSIZE+2]) & Link.MODE_BYTEMASK
+        else: return None
+
+    @staticmethod
+    def mode_from_lp_packet(packet):
+        if len(packet.data) > RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2:
+            mode_byte = packet.data[RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2:RNS.Identity.SIGLENGTH//8+Link.ECPUBSIZE//2+1]
+            return mode_byte & Link.MODE_BYTEMASK
+        else: return None
 
     @staticmethod
     def validate_request(owner, data, packet):
@@ -177,9 +206,9 @@ class Link:
             return None
 
 
-    def __init__(self, destination=None, established_callback = None, closed_callback = None, owner=None, peer_pub_bytes = None, peer_sig_pub_bytes = None):
-        if destination != None and destination.type != RNS.Destination.SINGLE:
-            raise TypeError("Links can only be established to the \"single\" destination type")
+    def __init__(self, destination=None, established_callback=None, closed_callback=None, owner=None, peer_pub_bytes=None, peer_sig_pub_bytes=None, mode=MODE_AES128_CBC):
+        if destination != None and destination.type != RNS.Destination.SINGLE: raise TypeError("Links can only be established to the \"single\" destination type")
+        self.mode = mode
         self.rtt = None
         self.mtu = RNS.Reticulum.MTU
         self.establishment_cost = 0