  The IPv6 over Low-powered Wireless Personal Area Network (6LoWPAN) protocol
was introduced to allow the transmission of Internet Protocol version 6 (IPv6)
packets using the smaller-size frames of the IEEE 802.15.4 standard, which is
used in many Internet of Things (IoT) networks. The primary duty of the 6LoWPAN
protocol is packet fragmentation and reassembly. However, the protocol standard
currently does not include any security measures, not even authenticating the
fragments immediate sender. This lack of immediate-sender authentication opens
the door for adversaries to launch several attacks on the fragmentation
process, such as the buffer-reservation attacks that lead to a Denial of
Service (DoS) attack and resource exhaustion of the victim nodes. This paper
proposes a security integration between 6LoWPAN and the Routing Protocol for
Low Power and Lossy Networks (RPL) through the Chained Secure Mode (CSM)
framework as a possible solution. Since the CSM framework provides a mean of
immediate-sender trust, through the use of Network Coding (NC), and an
integration interface for the other protocols (or mechanisms) to use this trust
to build security decisions, 6LoWPAN can use this integration to build a
chain-of-trust along the fragments routing path. A proof-of-concept
implementation was done in Contiki Operating System (OS), and its security and
performance were evaluated against an external adversary launching a
buffer-reservation attack. The results from the evaluation showed significant
mitigation of the attack with almost no increase in power consumption, which
presents the great potential for such integration to secure the forwarding
process at the 6LoWPAN Adaptation Layer
