Delay Tolerant Network Security

1. Delay Tolerant Network Security -a literary survey Venkata Krishna Sangeetha

2. In a bird’s view • Existing standard networks • Probing reasons for a new network • DTN in a few words • Architecture explained • Services • Is it perfect? • Threat Model • Why and what need for security? • Bundle: The Big Daddy • Schemes tabulated • Ending the discussion

3. Internet Today • Successful at interconnecting communication devices across the globe • Based on TCP/IP protocol suite and wired links • Connected in end-to-end, low-delay paths between sources and destinations • Low error rates and relatively symmetric bidirectional data rates

4. Why a Delay Tolerant Network? Intermittent Connectivity: TCP/IP protocols fail when network partitioning occurs. Long or Variable Delays: Long delays between nodes and variable queuing delays contribute to end to end delays defeating internet protocols and applications. Asymmetric Data Rates: Large asymmetries in data rates are not supported by the Internet. High error Rates: The error rate increases with the end-end retransmission of packets.

5. DTN Overview • Overlay network • Connecting disconnected or heterogeneous networks (network of internets) • Store-and-Forward network • Typical resource-challenged networks

6. DTN Architecture

7. DTN Services

8. Open Issues in Delay Tolerant Networks • Key Management: Lack of a key distribution service in a high delay/ disrupted environment. • Handling Replays: A generic DTN replay detection scheme is hard to determine. • Traffic Analysis: Protection against traffic is debatable. • Routing protocol security: Inherent uncertainty in the network makes routing a problem. • Multicast/ Anycast security: Current architecture does not support such endpoints. • Performance Issues: Tradeoff between security and performance due to the added overhead.

9. Threats/ Attacks Classification

10. DTN Security Requirements & Characteristics • Lack of end- to – end Connectivity: Traditional round key agreements do not work. • Fragmentation: Splitting of a message into fragments or “bundles”. • Resource scarcity: Contact time introduces limitations. • Bundle Accumulation: Store and forward approach may lead to bundle accumulation. • Authentication: Essential for every node to authenticate the data. • Confidentiality: Ensuring that the sensitive information is not revealed to unauthorized parties. • Integrity: To ensure that transmitted messages cannot be altered. • Privacy/Anonymity: User location should not be revealed.

11. Bundle Protocol Security • Data is sent in the form of bundles • Different types of blocks implemented to provide security services at various levels like hop-by-hop authentication, payload confidentiality and integrity in each bundle • Not all nodes have security capabilities

12. Bundle Security Protocol Specification • Bundle Authentication Block – ensure authenticity and integrity of bundle along a single security hop. • Uses HMAC • Payload Integrity Block – authenticity and integrity of the payload along the PIB security-source to PIB security-destination. • Uses RSA-SHA256 • Payload Confidentiality Block – indicates payload is encrypted to protect the content. • RSA-AES128-PAYLOAD-PIB-PCB • Extension Security Block – provides security for non-payload blocks in a bundle • RSA-AES128-EXT

13. Security Schemes

14. Drawing Conclusions • DTN is an overlay network connecting various types of networks • Security considerations for this type of challenging networks is difficult. • Security considerations for the below layers usually apply for this. • Current researching groups: * The Internet Research Task Force’s Delay-Tolerant Networking Research Group (DTNRG) * The InterPlaNetary (IPN) Internet Project, * NASA Jet Propulsion Laboratory * Google Laboratory * Intel Research Corporation, etc.