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| Author | Topic: Encrypted AIS or Blue Force AIS |
| jimh |
Very recently while reading an NTSB boating accident investigation report (see Note 1 below), I came across for the first time a mention of an encrypted AIS method that was being used by law enforcement vessels. After a bit of research on encrypted AIS I found the term "Blue Force AIS" was often used in conjunction with this method. Blue Force AIS or encrypted AIS refers to a method of vessel automatic identification system transmission in which the data about the vessel, such as its name, course, speed, and so on, is sent with encryption so that it cannot be received by standard AIS receivers. This permits vessels, particularly military or law enforcement vessels, which employ the encrypted transmission and reception equipment to track each other, but at the same time appear invisible to other vessels, that is not show up on conventional AIS equipment. In addition to data encryption, it appears that the Blue Force AIS transponders can also use different frequencies, specifically a band of radio frequencies known as MURS, an acronym for Multi Use Radio Service. Of course, transmitting the data on a different frequency than the standard AIS insures that it will not be received by standard AIS equipment. Here are excerpts from two vendor's literature describing the encrypted AIS or Blue Force AIS capabilities of their product:
quote: (See Note 2 for citation.)
quote:(See Note 3 for citation.) The term MURS appears to refer to a group of five VHF channels in the 151 to 155-MHz range which are available to citizens of the USA for use without a license, as long as the transmitter power is 2-watts or less, and subject to certain other restrictions. See http://en.wikipedia.org/wiki/Multi-Use_Radio_Service for more details. In the NTSB report (mentioned above), the following was quoted as being the USCG policy for operation of their AIS units:
quote: Based on the recommended operational setting (restricted mode), boaters should not anticipate seeing USCG vessels on their AIS receivers. Notes: 1. http://www.ntsb.gov/doclib/reports/2011/MAR1103.pdf , Section 1.15.2, Coast Guard AIS Policy. The section quotes Coast Guard directives regarding when use of encrypted AIS was appropriate. 2. http://www.prweb.com/releases/2006/06/prweb404338.htm is a press release from manufacturer Shine Micro, a Washington (state) based marine electronics manufacturer. 3. http://www.km.kongsberg.com/ks/web/nokbg0240.nsf/AllWeb/ 97583FFE2F31AD55C1257798002E384A?OpenDocument, from Kongsberg, a manufacturer of commercial grade marine electronics. |
| 6992WHALER |
That's interesting, In Canada this last summer a Canadian Coast Guard vessel showed on my AIS. |
| jimh |
In Canada, their Coast Guard is not operated as a military service. It is run more like a regular civil-service operation. In the United States, the USCG seems, now more than ever, to have become an adjunct of the military services, and their operation becomes more paramilitary, a distinct change from their previous and historical life saving, rescue, and safety mission. Above note that encrypted AIS is done in accordance with NATO STANAG 4668. A little research on NATO STANAG 4668 shows it is a warship automatic identification system. Apparently when Homeland Security talks about the war on terrorism they are not kidding, and your local USCG small boat now operates like a warship in hostile combat in regard to encrypted AIS. I have a very good friend who was a CWO4 in the Coast Guard Reserve and only recently retired or detached from reserve duty. He used to say that often they'd conduct patrols which he described as "showing the flag," which I interpreted to mean just having a presence on the water and letting people see the USCG vessel underway and on duty. It seems a bit incongruous that the USCG would recommend its vessels use only encrypted AIS transmissions while they were conducting routine, overt, and normal patrol. What better way to "show the flag" than electronically via an AIS transmission? |
| 6992WHALER |
I see your point, but if I wanted to sink a ship, it sure would be nice to know exactly what course and speed it was traveling. It is an interesting Catch-22. |
| David Pendleton |
It would appear that this [that is, the use of encrypted AIS as the recommended mode of operation for USCG vessels] is designed to deny the public the ability to monitor a vessel via AIS, as any government would have the ability to monitor the above-mentioned frequencies and determine a ship's presence and position based on that alone. |
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