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encryption and security

PostPosted: Thu Mar 22, 2018 11:22 pm
by philthespark
Hi all, I'm a newbie here but have been reading some of the posts with interest, especially some of those concerning digital radio and encryption. I can, having used the old police radio network understand the people who say that it is a better network, in the bad old days it always seemed you got a dead spot right when it was the last thing you wanted, however, you have to wonder about the security aspects of encryption, when the tetra radios first came out, it was said they would be only available to the emergency services, now you can get them, albeit wiped, secondhand on e-bay, surely it won't be too long before someone works out how to get them to pick up the police frequencies once again.
Back in the day, when it was all analogue, I remember you could get the police channels at the top end of any decent FM radio, then they moved them, then along came the scanner and people could listen in once more.I had a mate back then who worked for the home office, his job was fitting radio's in police cars, Nearly everybody who worked there had an old radio with a set of crystals in so they could listen at home, and the beauty of working there was you knew exactly what frequency was used in which force area, and which department used what, so unlike with a scanner, where quite often you could only hear either the base or the mobile, with the proper kit you could hear it all.
I remember at the time the organisation I worked for handled security for local government buildings, if a call came in, both ourselves and the police would be dispatched, thereby ensuring a very fast response time, by either us or them, it didn't matter who got there first as long as someone did. One day the unthinkable happened, one of our team lost a walkie-talkie, someone found it and after a week or two of playing silly beggars, they, or someone they knew, settled down to working out exactly how our system worked, unfortunately, there was no way to block the unit without affecting all the others, we just had to hope they'd either get bored or something would happen to the radio,it didn't. we had to maintain a strict radio procedure back then, each building had a call-sign, and so did each patrol, they worked part of this out and we had a couple of break-ins as a result. We changed the call-signs and got everything back to normal, we even had some cheeky sod offering us the radio back for a "finders fee" when they realised it was of no further use.
One thing I have noticed in the last few years is the standard of RT procedure seems to have fallen badly, things are often mentioned over the air that wouldn't have been back in my day, A couple of years ago I was helping a mate out with a problem at a nightclub, it was decided the only solution was to bring in a dog handler, now having done this in the past, and still having a working dog, I was the first person he approached to help him. The job went well for the first week, trouble was reduced massively, obviously to the thugs who had been causing bother, tackling a bouncer was one thing, tackling a handler with a large German Shepherd was an entirely different matter, then one night it all kicked off.
It wasn't as spectacular as you may have thought, no gang of thugs armed with baseball bats, rather just one drugged up nutter with a bicycle! When it was all over I had to go to the police station to do the paperwork and the front desk was in typical Friday night mode, in short, chaotic. Knowing on or two of the cops on the night shift I was invited into the back, "we'll grab a coffee while we do the paperwork" said one of the lads who'd attended the job.We went in the back and sat at a table in a small "brew room", there were several other cops in there and on one of the tables was a radio, it was set to group mode and you could hear everything that was happening, a couple of domestics, a car smash, drunks fighting,you name it, it was going on.
What struck me most about it was I was able to completely understand every word, gone were the IC codes, instead it was "a white male approx 5'8" tall, most of the callsigns had disappeared as had most of the RT procedure I knew from way back. no matter how much they encrypt transmission unless they go back to using the correct "radio language" then it will only be a matter of time before the encryption becomes an expensive white elephant, after all, what is the point in asking an officer at an incident if his radio is secure, while they pass on some important piece of information, often the informants details, if there are several other officers nearby also on that channel whose radios are on open speaker.

Re: encryption and security

PostPosted: Fri Mar 23, 2018 9:23 am
by Minus1
A think you generally right. Clever techniques are far cheaper and reliable than encryption.

There is obviously an overhead on encryption. Some organizations have one talkgroup encrypted whilst another is not. If encryption had no overheads (technical or financial) they wouldn't do that.

Sometimes there is a good technical reason for encrypting: USAF Fairford encrypt most thtalkgroups, but not the tower talkgroup which relays what is transmitted on UHF AM. Obviously if you have the audio in the clear on one channel, but encrypted on another, you could potentially use it to analyze the encryption technique.

Most military air comms are not encrypted because there are problems with doppler effects when two aircraft are travelling at high speed in various directions.
Navy tactical callsigns use a format like letter-digit-letter or digit-letter-letter. They change every day. Sometimes you might recognize the same voice the next day using a different callsign, so might know it's the same ship (unless they are really devious and swap personnel between ships ;-)

Now and again you can still hear fire service control rooms when an engine uses its UHF fireground repeater linked to its TETRA radio. The protocol sounds much like it ever was.

Most emergency service comms in the US are not encrypted; and many (if not most) media monitor local public safety communications; so there is none of this vague "police are dealing with an incident" nonsense much abused by British police. The US media complain vigorously about free speech, and freedom of the press, if some agency tries to encrypt things.

TETRA was pretty much forced on us by the EU, when (if) we ever get out, there is always to possibility that sense will prevail again.

Re: encryption and security

PostPosted: Fri Mar 23, 2018 2:13 pm
by philthespark
Totally agree with you, it's a bit like getting an expensive burglar alarm on your house then not locking the doors! I personally having worked with the police, love the"dealing with an incident" speech, it doesn't half wind them up when they realise you know what they are doing. I remember a few years ago, there'd been a robbery near me, the thief had abandoned the car and was garden hopping, there was police everywhere, even the helicopter was up, I thought I had seen someone at the bottom of my garden and went out to have a word with one of the coppers who were on my front, "too busy mate, we've got an incident going on" said one when I mentioned the prowler, he radioed for another patrol to attend rather than investigate himself, the other patrol arrived, single crewed, but didn't fancy going looking for the bloke as he thought he may have been the robber and was violent. Meanwhile all the cops in our street had gone tearing off down one of the next streets, "I think we need a dog unit" he said, standing in the garden, "but they are all busy I think", I looked in amazement, "hang on a minute, I'll be back" I replied, I went upstairs and got my old gear out of the wardrobe, body armour, handcuffs, torch and baton, I quickly put my kit on, threw a harness on the dog and we both went outside, "right, one dog unit on scene, lets find the criminal shall we". We searched our garden and the neighbours, and found him hiding in a shed! What a result, a quick call on his radio and the mob of coppers returned, they came legging through our front door and all congregated in my back garden, the man was handcuffed and led away, one of the coppers looked at me, "I'll pretend I haven't seen you with that baton, ok?" and with that they all disappeared.
I think sometimes if they only spoke nicer to members of the public, they'd get a much better result, sadly I feel a lot of it now is down to the uniform, yes it's a lot more practical than the old shirt and tie, but for me it looks a bit paramilitary and I think some of the young bobbies fancy themselves as a cross between Judge Dredd and Rambo. It would pay them to remember who it is that actually walks the streets on a daily basis, and in the current climate where they are virtually a blue light only service it's the likes of you and I who are on the streets every day, therefore it is us who more often than not are the ones who know who the drug dealers are, or the burglars, and it's only by talking to us that they will find these things out.