1. Space Data Link Secure Protocol Interoperability Testing Interfaces Definition Proposal Bruno Saba DCT/TV/IN 26/04/2010

2. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 2 Interfaces between two distant simulators ■Data Interfaces  Connecting one or more « useful » data stream  TC or Forward link(s)  TM or Return link(s) ■Control Interfaces  Used for exchange of data relative to the simulators’ management  « Synchronisation » data –Simulation starting time –…  Others –Simulator results –Files for comparison –…

3. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 3 CNES’ Proposals ■1st step of Interoperability Testing  Main goal : KEEP IT SIMPLE !  The objective is to validate the protocol, not to build a complex network system  Use UDP/IP for data streams  TC or Forward Link  TM or Return Link  UDP/IP is a well defined and well known protocol  No need for special hardware or software  Easy to implement  No flow control, some packets can be lost (like in the « real life » of the protocol)  Can be used on-line between two distant simulators, or off-line on localhost  Already used in CNES’ simulator

4. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 4 CNES’ Proposals ■1st step of Interoperability Testing (cont’d)  On-line or Off-line simulations  On-line : direct communication via UDP/IP  Off-line : exchange of files  Use e-mails or telephone for control data  Simulations Starting time / Ending time scheduled by emails  File exchange by email –Transfer of data files for comparison purposes –Transfer of simulation results  Use of phone if needed…  Use of TCP/IP for synchronisation purposes only on the 2 nd step, only if needed

5. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 5 What do we need to agree on ? ■Interfaces between simulators (easy…)  UDP/IP for data  Emails or phone for control ■First implementation of the SDLS protocol ! (not so easy…)  SDLS protocol baseline  Secure services (authentication, encryption, authenticated encryption)  Algorithm(s) and modes of operation  Security Association / Security Context convergence… DONE  Position of Security Layer (TC Link) DONE  Security header definition DONE  Security header position DONE  …

6. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 6 First implementation of the SDLS protocol ■Services provided  Clear mode  Authentication only (AO)(TC,TM)  Authenticated Encryption (AE)(TC,TM)  Encryption Only (EO)(TM Only)  No switching management between services ■Algorithms and modes of operation (same algorithms for TC and TM)  AES GMAC (for AO)  AES GCM(for AE)  AES CTR (for EO) ■No special Key Management  Exchange of Keys between two simulators before simulation session ■No Security Association Dynamic Management  Agreement on the content of the SA to be used before simulation

7. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 7 First implementation of the SDLS protocol ■TC link (or Forward link)  Transmission of the complete CLTU ?  Including Start Sequence (EB90) and Tail Sequence  This would allow future testing of hardware implementation of the protocol  COP-1 Implementation ?  May be useful to see possible interaction between COP-1 and SDLSP…  Position of Security Header  Just after the Transfer Frame Primary Header (as defined in 132.5-W1 Nov 2009)

8. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 8 First implementation of the SDLS protocol ■TC link (cont’d)  Security Header Definition  Sequence Number : not needed, Initialization Vector and Authentication service providing anti-replay protection  Initialization Vector : 4 Bytes  Key Index : not needed for TC link  PAD length : not needed  Security Header total length : 6 Bytes  Trailer (Message Authentication Code) length : 16 Bytes

9. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 9 First implementation of the SDLS protocol ■TC link (cont’d)  Security Association Definition  Each Security Association must contain –Global MAPID(s) to which it is assigned –Service provided (Clear, AO, AE) –Key  Initialisation Vector Management  4 byte counter  Generated by the ground segment  On-board control mecanism : new received IV must be greater than the previous one  Guarantees IV uniqueness  Also provides anti-replay service

10. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 10 First implementation of the SDLS protocol ■TM link (or Return link)  Transmission of the complete CADU ?  Including Start Sequence (1ACFFC1D) and Tail Sequence  This would allow future testing of hardware implementation of the protocol  Position of Security Header  Just after Frame Secondary Header (if present) (as defined in 132.5-W1 Nov 2009)

11. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 11 First implementation of the SDLS protocol ■TM link (cont’d)  Security Header Definition  Sequence Number : –Not needed if Encryption Only mode is not used, Initialization Vector and Authentication service providing anti-replay protection –When using EO mode, counter on IV provides anti replay protection  Initialization Vector : 6 Bytes ?  Key Index : 2 Bytes  PAD length : not needed  Security Header total length : 10 Bytes  Message Authentication Code (trailer) : 16 Bytes

12. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 12 First implementation of the SDLS protocol ■TM link (cont’d)  Security Association Definition  Each Security Association must contain –Global Virtual Channel(s) to which it is assigned –Service provided (Clear, AO, AE, EO) –Key set (key selection by key index)  Initialisation Vector Management  6 byte counter  Generated on-board  On-board generation guarantees no regression : new IV sent is greater than the previous one (+1)  Guarantees IV uniqueness  Also provides anti-replay service

13. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 13 Conclusion ■Development of the simulators can start as soon as everybody agrees on the first implementation of the SDLS Protocol ■Interoperability Testing would then begin step by step  TM Link  TC Link (no COP-1)  TM Link and TC Link  TM Link and TC Link with COP-1

14. SDLS - Interoperability Testing - Interfaces Definition Proposal CNES B. Saba 14 Thank you for your attention