1. INRIA Rhône-Alpes - Planète research group Reed-Solomon FEC I-D LDPC-* FEC I-D TESLA I-D Simple-auth I-D IETF 70 th – Vancouver meeting, November 2007 Vincent Roca (INRIA)

2. 2 - INRIA - Planète Situation Reed-Solomon FEC draft-ietf-rmt-bb-fec-rs-05.txtupdated LDPC FEC draft-ietf-rmt-bb-fec-ldpc-07.txtupdated TESLA source authentication for ALC/NORM draft-ietf-msec-tesla-for-alc-norm-03.txtupdated Simple auth. schemes for ALC/NORM draft-roca-rmt-simple-auth-for-alc-norm-01updated

3. 3 - INRIA - Planète Part 1: Reed-Solomon FEC BB

4. 4 - INRIA - Planète What’s new with the R-S document? “publication requested” in Sept. 2007  “proposed standard” category two versions published  -04 (Oct. 2007) and -05 (Nov. 2007)  version -05 takes into account comments on mailing list (Igor Slepchin and Alfred Hoenes):  corrected error in “Determining the Max Src Block Length”  changed the way the max_n parameter is calculated (floor  ceil) from the target code rate for a better match

5. 5 - INRIA - Planète What’s new with the R-S document (cont’)  clarified that the “max_n algorithm” is only RECOMMENDED to be used. Receivers can estimate “n” for a given block, but MUST be prepared to handle symbols with an ESI > “estimated n”  takes into account comment sent during IESG review (Magnus/Francis Dupont/Elwyn Davies/Stephen Kent/Russ Housley)  a brand new « Security » section (but too detailed ;-)  several details corrected… next step:  new version (-06) under progress

6. 6 - INRIA - Planète Part 2: LDPC-staircase/triangle FEC BB

7. 7 - INRIA - Planète What’s new with the LDPC-* document? “publication requested” in Sept. 2007  “proposed standard” category one versions published  -04 (Oct. 2007) and -05 (Nov. 2007)  version -05 takes into account comments on mailing list (Alfred Hoenes + Igor Slepchin indirectly)  better separation between mandatory and recommended procedures  changed the way the max_n parameter is calculated (floor  ceil) from the target code rate for a better match (no backward compatibility impact)

8. 8 - INRIA - Planète What’s new with the LDPC-* document (cont’)  takes into account comment sent during IESG review (Magnus/Brian Carpenter/Russ Housley/Jari Arkko)  a brand new « Security » section (but too detailed ;-)  several details corrected…  removal of the C code’s copyright (with the permission of the authors and R. Neal)  updated PRNG section: the scaling in [0; maxv[ algorithm is mandatory C implementation moved in annex (will be replaced by a pointer in next version, as agreed with Robin Whittle) next step:  new version (-07) under progress

9. 9 - INRIA - Planète Part 3: TESLA for ALC and NORM

10. 10 - INRIA - Planète What’s new? most changes already done in -02 version (July 07)  reminder:  compact authentication tag without the “i” interval index field but instead one or two sub- fields when feasible  authentication tag without key disclosure to reduce packet’s overhead  optional embedded group MAC feature  current version only improves the text, no new feature

11. 11 - INRIA - Planète (Very preliminary) performance results test conditions:  512000 packets send, 512 bytes/packet (total of 250 kB)  HMAC-SHA-1 with 160 bit keys  100 keys per TESLA key chain, 0.5s TESLA time interval  measure the time taken to send all packets (no receiver) results (sender):  TESLA (W/O group MAC): 6.362 s  Group MAC authentication: 6.063 s  Digital signatures authentication:776.548 s  TESLA is only 4.93% slower than Group MAC auth. more detailed performance analysis under progress

12. 12 - INRIA - Planète Work under progress under progress…  we need to finish TESLA for ALC implementation (soon)  useful to check the accuracy of the document  we need to verify in particular the steps specified in  5.2 Authentication of received packets open points/questions to the group  do we keep the optional weak group MAC?  or do we add an external group MAC authentication scheme (I-D under progress) that can be used in the same session?  would simplify the specs, but adds more overhead  clarify what parameters are needed with digital signatures

13. 13 - INRIA - Planète Part 4: Simple authentication schemes for ALC and NORM - slides already presented during IETF’69 -

14. 14 - INRIA - Planète Simple auth schemes for ALC/NORM an I-D…  that defines two basic authentication schemes for group communications  shares the EXT_AUTH format  ASID field is used goal is to have an appropriate set of authentication schemes for group comm.  for per packet, transport level (i.e. within ALC/NORM) security  it’s complementary to IPsec layer 3 security

15. 15 - INRIA - Planète Simple auth schemes for ALC/NORM… (cont’) pros/cons in short +----------------+-------------+--------------+-------------+-------+ | | RSA Digital | ECC Digital | Group MAC | TESLA | | | Signature | Signature | | | +----------------+-------------+--------------+-------------+-------+ | True auth and | Yes | Yes | No (group | Yes | | integrity | | | security) | | | Immediate auth | Yes | Yes | Yes | No | | Processing | -- | + | ++ | + | | load | | | | | | Transmission | -- | + | ++ | + | | overhead | | | | | | Complexity | ++ | ++ | ++ | -- | | IPR/patents | ++ | -- | ++ | ++ | +----------------+-------------+--------------+-------------+-------+

16. 16 - INRIA - Planète Simple auth schemes for ALC/NORM… (cont’) example: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HET (=1) | HEL (=33) | ASID | 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | + |.. Signature (128 bytes).. | + | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HET (=1) | HEL (=4) | ASID | 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | + | Group MAC (10 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Digital Signature EXT_AUTH header extension using 1024 bit signatures Group MAC EXT_AUTH header extension using HMAC-SHA-1. 128 bytes 12 bytes

17. 17 - INRIA - Planète To conclude with simple auth schemes it’s the logical follow-up to TESLA I-D  provides a comprehensive set of techniques for the most basic security feature: source authentication and packet integrity a WG Item?