Paper Survey. Secure CoAP scheme for Internet of Things. DTLS, 6LoWPAN constrained environment. http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6576185

1. Lithe: Lightweight Secure CoAP
for the Internet of Things
Master’s Degree 29th
Park. Joon-young

2. Contents
• Introduction
• Backgrounds
• Scheme
• Implementation
• Evaluation
• Conclusion
• Question & Answer

3. Introduction
Limited Processing Power
Limited Storage
Low Bandwidth
Inefficient Energy
Sensors will have..

4. Backgrounds
IPv6 over Low-power Wireless
Personal Area Network
IEEE 802.15.4 / a.k.a Zigbee
UDP Based
IPHC / NHC
(IP/Next Header Compression)
Well-designed
Header Compression
Automatic Key Management
Data Encryption
Integrity Protection
Authentication
DTLS is Heavy
(Not suitable for IoT)
6LoWPAN CoAP / DTLS

5. CoAP
• Substitutes HTTP’s RESTful structure on UDP
• GET, POST, PUT, DELETE..
• Cacheing, Proxing

6. DTLS

7. DTLS

8. DTLS-6LoWPAN
• Define a new NHC for UDP with different ID bits.
• Extension to the 6LoWPAN standard.
• UDP payloads contains compressed DTLS Headers

9. 6LoWPAN-NHC-RHS / R
• Version (V)
• Epoch (EC)
• Sequence Number (SN)
• Fragment (F)
Record + Handshake / Record only

10. 6LoWPAN-NHC-CH
• Session ID (SI)
• Cookie (C)
• Cipher Suites (CS)
• Compression Methods (CM)
ClientHello

11. 6LoWPAN-NHC-CH
ClientHello

12. 6LoWPAN-NHC-SH
• Session ID (SI)
• Cookie (C)
• Cipher Suites (CS)
• Compression Methods (CM)
ServerHello

13. 6LoWPAN-NHC
• ServerHelloDone / ClientKeyExchange / Finish
have no fields to be compressed.
• ServerKeyExchange is mostly not sent
Other Messages

14. Integration
• OS - Contiki
• tinyDTLS - TLS_PSK_WITH_AES_128_CCM_8
• Platform - WiSMote

15. Contiki
• OpenSource OS since 2002
• For networked, memory-
constrained system (IoT)
• needs 10k RAM / 30k ROM

16. Integration
• pre-configured default DTLS port is used
• DTLS Port
• ID bits in NHC-for-UDP
• NHC for DTLS headers
Input Packets
Output Packets
Distinguishing packets whether DTLS or not

17. Evaluation
- Packet Size Reduction

18. Evaluation
- RAM & ROM Requirement

19. Evaluation
- Run-Time Performance

20. Evaluation
- Run-Time Performance

21. Evaluation
- Run-Time Performance
RTT(Radio Trip Time) / RDC(Radio Duty Cycling)

22. Conclusion
• Reducing overhead of DTLS using 6LoWPAN header
compression
• The first DTLS header compression specificatino for
6LoWPAN
• Reduce the CoAPs overhead and gain efficiency for
energy consumption and network-wide response time.
• Avoid 6LoWPAN fragmentation, we did not
compromised against possible attacks.