A company called Certified Time offers secure NIST-based time data and has
many unkind things to say about the integrity of GPS time signals. You
might find some useful references among the documents they have posted at
http://www.certifiedtime.com/site/repository/index.html
At 09:24 AM 5/8/00 +0300, [EMAIL PROTECTED] wrote:
>
>
>I'm looking for info on GPS security, specifically, its integrity /
>authentication mechanisms to protect against spoofing.
>This is important since many systems assume GPS is a secure source of time
>and location. (My interest in this began as we are completing paper on
>proactive secure clock synchronization, and figured we ought to compare
>this to the approach of using GPS receivers to provide secure time.)
>
>As recently discussed on this and other lists, the accuracy of commercially
>available (civilian) GPS has recently been improved by the removal of the
>Selective Availability degradation of the Coarse Acquisition (C/A) signal.
>However, after (very limited) digging up some GPS papers/web sites, I
>didn't find any mention of authentication/integrity/anti-spoofing
>mechanisms to the C/A signal. I did find a brief mention that the (still
>encrypted) P/Y signal has some anti-spoofing mechanism; but I didn't see
>any details on how that is done (such details may be confidential).
>
>I'm interested in both the C/A and the P/Y integrity mechanisms. The
>anti-spoofing of the P/Y signal is, to me, more of academical interest. I
>find the C/A signal integrity more interesting as it is available for
>commercial use. How hard is it to spoof it? Is there any real difficulty in
>protecting its integrity ? Or is it protected well?
>
>Thanks for any help/info.
>
>Best Regards,
>Amir Herzberg
>
>IBM Research Lab in Haifa (Tel Aviv Office)
>http://www.hrl.il.ibm.com
>
>
>
