Bluetooth 4.0 specifies 128 bit AES CCM mode. http://www.bluetooth.com/Pages/low-energy-tech-info.aspx Also found in IEEE 802.15 (Personal Area Networks). The 802 standards can be downloaded without cost for personal use. You have to be Bluetooth SIG member to get Bluetooth standards and they don't accept individual members. IEEE Std 802.15.1-2005 13.4 appears to describe the earlier encryption method E0 and LFSR with a 128 bit key. Annex B of IEEE Std 802.15.3b-2005 LOCAL AND METROPOLITAN AREA NETWORKSbPART 15.3: WIRELESS MAC AND PHY, specifies security considerations using AES addressing key usage and replay prevention. Without further evidence you could wonder whether or not they use E3 (SAFER+ based hash) to generate keys for AES as well (802.15.1-2005 13.6). Key exchange is upper layer stuff. Taking a lot at the previous encryption method EO (which also used a 128 bit key) see NIST Special Pubs SP800-121, Guide to Bluetooth Security[1] which also refers to a recent (CRYPTO'05) study saying 2^^38 computations and 2^^23.8 frames resistance for E0[2], also See Table 4-1. Key Problems with Existing (Native) Bluetooth Security. There doesn't appear to be a real time threat. If you include financial transactions or other high security dependent on using two factor security you need to have penetrated that too (oops), it serves as a real time anchor. You could note that the government wasn't setting off any alarms on the use of the previous method although providing quidelines and qualifying the risk[3][4]. The image here is that AES is a jump on the bandwagon response to an non-articulated problem. It'd make sense increasing the throughput to increase the security, for those things that can take advantage of a higher data rate. The new range (100m) for Bluetooth 4.0 sounds like a threat even without fancy antennas. I opened the curtains in my office and took some binoculars out in the yard along with a bluetooth device. Amazing the range on these things. You'd expect government bluetooth security guides would get updated, security is likely still be use and implementation dependent and the question still remains, how serious the threat is. Feel free to use the keyboard built in to you laptop to avoid it. Hey, is that someone with a spotter scope looking at your computer screen from across the street? Back in the days before SCIFs were quite so prevalent the euphemism was 'step into my office', a moving vehicle was considered safe. Both conditions have changed since then and I'm enjoying the lack of professional paranoia these days. We were much more likely to find illicit drug stashes than listening devices searching cable troughs, equipment rooms and offices. There's undoubtedly a distinction in the level of effective security between the average Microsoft customer feeling secure because of buying one of these keyboards and a security conscious organization implementing guidelines and adhering to recommendations. The amount of security you end up with in the two cases is only in part affected by the encryption algorithm selection. ------------------------------ [1] Guide to Bluetooth Security SP800-121, http://csrc.nist.gov/publications/nistpubs/800-121/SP800-121.pdf [2] The Conditional Correlation Attack: A Practical Attack on Bluetooth Encryption, Y1 Lu, Willi meier and Serge Vaudenay http://lasecwww.epfl.ch/pub/lasec/doc/LMV05.pdf http://www.iacr.org/conferences/crypto2005/p/16.pdf (slides) [3] Bluetooth Security http://www.nsa.gov/ia/_files/factsheets/I732-016R-07.pdf [4] Recommended Security Controls for Federal Information Systems and Organizations http://csrc.nist.gov/publications/nistpubs/800-53-Rev3/sp800-53-rev3-final_u... See pages F-15, F-16, Page A-9 _______________________________________________ cryptography mailing list cryptography@randombit.net http://lists.randombit.net/mailman/listinfo/cryptography ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE