Lightweight security protocols for the IoT Shahid Raza PhD, Senior Researcher SICS Swedish ICT, Kista shahid@sics.se

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Internet of Things (IoT) Network of globally identifiable physical objects/things Mostly resource-constrained, lossy wireless networks Multi-hop Unattended deployments Extremely heterogeneous IPv6, an IoT enabling technology and integration layer IPv6 over Low power Wireless Personal Area Network (6LoWPAN) IPv6 Com. IPv6 6LoWPAN Border Route (6BR) 6LoWPAN Internet

IoT Security Internet Communication Security Network Security Confidentiality Integrity Authentication Network Security Availability Data-at-rest Security Confidentiality Integrity Software Security IPv6 com. IPv6 6BR Internet 6LoWPAN

Communication Security in the IoT Solution developed in FP7 CALIPSO are being used in H2020 NobelGrid

Communication Security in the IoT Per hop security End-to-End (E2E) security com-IPv6 IPv6 Internet 6BR Internet protocol based Lightweight but compliant with existing standards.

IoT and Security Protocols CoAP, CoAPs DTLS comp. DTLS UDP comp. UDP IPv6 com. IPv6 IPsec com. IPsec Ethernet/WiFi 802.15.4 security HTTP CoAP TLS DTLS IPv6 com. IPv6 IPsec Ethernet 802.15.4 UDP Comp. UDP CoAP, CoAPs UDP DTLS IP RPL IKE/IPsec 6LoWPAN IEEE 802.15.4 HTTP/HTTPs, CoAP/CoAPs TCP, UDP TLS, DTLS IP IKE/IPsec Ethernet 6BR Conventional Internet 6LoWPAN Standard compliance is the key. E2E security is the key

Secure CoAP (CoAPs) CoAP enables secure web in the IoT HTTP + TLS = HTTPS Reliable and synchronous transport (TCP) CoAP + DTLS = CoAPs Unreliable and asynchronous transport (UDP) coaps://mySite:port/myResource https://mySite:port/myResource Actual overhead comes from DTLS

The DTLS Handshake 9

Extending 6LoWPAN-compression to DTLS ClientHello is the first message sent to establish a secure session and for negotiation of crypto algorithms. The current 6LoWPAN specification define compression schemes for UDP/IP protocol. IP Datagram with ClientHello Compressed ClientHello

Lightweight DTLS Header size comparison DTLS Header Without Compression [bit] With Compression [bit] %Saving Record 104 40 62% Handshake 96 24 75% ClientHello 336 264 23% ServerHello 304 14%

Lightweight DTLS Example: IP datagram with ClientHello Protocol Uncompressed [bytes] Compressed [bytes] IP 40 7 UDP 8 4 DTLS Record 13 DTLS Handshake 12 ClientHello (Minimal) 42 17 Total 115 35 Shahid Raza, et al., Lithe: Lightweight Secure CoAP for the Internet of Things. IEEE Sensors Journal, 13(10), 3711-3720, October 2013.

IP security (IPsec) End-to-End security at the network layer Authentication Header (AH) Integrity and authentication Encapsulated Security Payload (ESP) Confidentiality and optionally integrity and authentication Transport and Tunnel modes Manually shared keys or use Internet Key Exchange (IKE) Recommended for IPv6 Compare it with DTLS https://tools.ietf.org/html/draft-raza-6lo-ipsec-04

IEEE 802.15.4 Security Per-hop security at the link layer The application controls the security required By default – “NO Security” Four types of packets Beacon, Data, ACK, Control packets for MAC Layer NO Security for ACK packets Shahid Raza, et al., Secure Communication for the Internet of Things - A Comparison of Link-Layer Security and IPsec for 6LoWPAN. Journal of Security and Communication Networks, 7(12), 2014

Security vs. Flexibility Per hop At lower layers Header protection too Protocol agnostic End-to-End (E2E) At upper layers Protocols bound

Lets use them SICSthSense Contiki OS Open source open license operating system for IoT implementations of most IoT protocols IPv6 6LoWPAN CoAP, RPL IEEE 802.15.4 IPsec IKEv2 DTLS, etc. OAuth 2.0 (Coming…) SICSthSense An open source and open license cloud platform for IoT

Performance Evaluation

DTLS Handshake – Different Security Modes

DTLS Handshake – Individual Messages

IPsec vs. IEEE 802.15.4 security Multi hops with 512 byte data size Average Response Time [ms] No. of hops

Key Management in IoT Security Modes Pre-shared key (PSK) – State-of-the-art in sensor network Raw-public key (RPK) Certificate-based - State-of-the-art in Internet

DTLS with Scalable Symmetric Keys An IoT node needs to recognize and remember only one device, the Trust Anchor (TA) DTLS Standard compliant Standard compliance is the key. Kc becomes a pre-shared key. Also for RPK Shahid Raza, et al., S3K: Scalable Security with Symmetric Keys - DTLS Key Establishment for the Internet of Things. IEEE Transactions on Automation Science and Engineering, 2016

Digital Certificates in the IoT Certificate based cyber security protocols Datagram TLS (DTLS) IKEv2/IPsec Object security IoT Standards specifying digital certificates CoAP LwM2M IPSO Objects ETSI Enrollment Process of certifying digital keys/certificates

A Current Research Project The CEBOT project: It aims to equip IoT devices with capabilities that will enable them to obtain digital certificate(s) in a secure and automated way and by using the communication protocols that these devices speak. Partners SICS Swedish ICT, Stockholm Technology Nexus (neXus) Endorsers

Conclusions IoT is nothing but an Internet 6LoWPAN is the main enabler for IoT 6LoWPAN is a generic way to connect constrained networks with the Internet and it can be applied to security protocols Communication security in the IoT can be achieved using standardized Internet security protocols. Both IPsec and DTLS are feasible to use in the IoT Lightweight IKEv2/IPsec and DTLS have similar overhead Compressed IPsec is more efficient than IEEE 802.15.4 security for multi-hop network with bigger data sizes

Thank you! Questions? Source code and publications: www.ShahidRaza.info Part of the work is carried out within the SIA Internet of Things, a joint effort by VINNOVA, Formas and the Swedish Energy Agency