Encryption Techniques - Analogue cable

HarryD

I've noticed two types of encryption techniques in use in Ireland for pay channels on analogue cable.
There's the standard Jerrold system which has a 'wavey' type (video sync ? ) encryption, and then I noticed a different type
in use in Dublin City.
It looks very similar to the old analogue satellite encryption.
(Fine horoziontal Lines) where the audio is un-encrypted.
Anyone know what type of encryption this is ?
Any what type of STBs NTL (or whoever) use to de-crypt ?

TIA<
HarryD

Mossy Monk

Originally posted by HarryD
It looks very similar to the old analogue satellite encryption.
(Fine horoziontal Lines) where the audio is un-encrypted.
Anyone know what type of encryption this is ?

Videocrypt?

DMC

Careful now... don't want to turn this thread in a discussion about hacking... That is banned here.

But continue on.

Typedef

Seriously though, you'd have to have ripped off hardware, to decrypt a signal.

No way would you have enough computational power to decrypt a TV signal real - time

Unless you were running your brute force analysis software on something like a Beowolf cluster......

A powerful one at that... say with 10-50 P4s running threaded and well optimised code....
50, probably more like.

maybe

In which case you would have... oh
150ghz of computational power to throw at each frame...

Though... of course once you cracked the key... you'd be sorted....
Wouldnt' have to brute force each frame.

I suppose it would depend on how often the keys were changed.....
One pass on a P4 .... each time the key changed might be costly in terms of time... but... less costly then the entire Beowolf - p4 x 50 paradigm.

Though, you might need such computational power.... if the keys are sufficiently large...

And again... how does one define a 'decrypted' stream, if not by eyeballing the results of a frame?

Emerson

NTL use "Cryptovision" (it says it on the front of their decoders).. it's similar to videocrypt, only it doesn't wash out the colour into pink/purple/greys.

BTW typedef, you'd be surprised. I won't discuss it here, but there are many who use software decoders on cable in the UK etc. for this particular encryption.

HarryD

Originally posted by Emerson
NTL use "Cryptovision" (it says it on the front of their decoders)..

interesting..
Do u know what model of decoders they use here ?
HD

Emerson

They are converted Pace recievers.. very similar to the old analogue videocrypt ones, used for sky back in the day.

They have a vhf/uhf tuner instead of 10+ghz, there is indented plastic where the card slots would be on the satellite receiver and of course a Cryptovision decoder.

Of course, it's not going to matter much longer as ntl are rapidly fasing out the service and migrating it to digital.

LegacyUser

I'm using one of those Pace Cryptovision boxes in the bedroom still — hasn't been paid for in two years ... originally from a different NTL region. I was told by NTL in April that the movie channels had been removed from analogue (I was watching Movie Max1 at the time), so as for NTL 'phazing' out the channels, I'll believe it when i see it in Galway ... the heads in Dublin don't seem to have a clue what;s going on down here.

HarryD

Can they address them decoders individually
as they can with Jerrold ?
Or is it a buy one - buy all deal where the supply
you with the decoder only if u buy all the pay channels..

HD

jmcc

Originally posted by HarryD
Can they address them decoders individually
as they can with Jerrold ?

The Cryptovision system is a far superior system to the Jerrold one. (I know the guy who designed it. ) It is fully addressable. However I don't know what use NTL/Cablelink made of its more advanced features since PayTV was never really a big seller on Irish cable. The wider range of programming on satellite tv and the limited channel allocations on cable tended to make people opt for satellite over cable.

The Jerrold system is based on synch suppression, a technique that is very old and very insecure. It is also a piece of sh1te from an engineering viewpoint because it interferes with the signal. The attraction of the system for cable operators is that it is a cheap piece of sh1te. The security model of Jerrold is very poor as well.

The Cryptovision system is more elegant in that it uses line cut and rotate as the scrambling. There is an audio encryption facility as well that was NICAM based from what I remember (It was developed in 1989-1990). I don't think that the NTL/Cablelink model used the audio encryption. Either it was too expensive to use audio encryption (highly probable) or it wanted to leave the audio in the clear as a 'barker channel' to let people know what they were missing.

The benefit of Cryptovision was that the scrambled signal was straight PAL with the synch pulses in the correct places.

However piracy of cable systems is illegal in this jurisdiction.

Regards...jmcc
[Writing as someone who knows a few things about Conditional Access Systems ]

HarryD

Originally posted by jmcc
The Cryptovision system is a far superior system to the Jerrold one. The Jerrold system is ...a piece of sh1te ]

Yeah... I must agree.. it is very weak..
I read up on the Jerrold system some time ago in an attempt to understand how it all works (addressability)..
Quite a weak system indeed..
Although the designers did include some half decent security measures such as the global timer command.

Now cryptovision is a new one..
Any good links/info on how it works ?

You gotta admire Sky Digital for designing a rock solid system.

R

watty

There is nothing good about the Jerrold system.
It was for NTSC cable and should never have been allowed.
It also has security of wet paper, which is why cryptoworks is used instead in some areas.

The Pace Analog Satellite receivers used a separate decoder card and there may have been FTA version for Europe market.

Analog Satellite was and is FM video, so the pace boxes must have an AM video demodulator instead of the FM. So they arn't simply Analog Sky boxes with Videocrypt replaced by cryptoworks.

Keyless decryption *IS* available for the most secure analog encryption which was/is syster/nagravision (There is a Digital Nagravision, but that is a different system).

It takes about 1minute to decode a frame (frames are 25 per second, 1/2 frame fields 50 per second) without key for nagravision.

Any modern PC can decode *ANY* video encryption system in real time if you know how it works *AND* have the keys. Which on some systems can change daily.

I'm sure all of the analog systems now have "hacks" though some arn't very practical.

Most of the Digital providers are moving to un-compromised second versions (seca-2 viaccess2 etc) except Sky/NDS. Though videoguard has been getting new cards, there are no actual confirmed hack of the Sky system (Even if a CAM is emulated, this is not a hack as the real viewing card is still needed.)

Piracy is an idiot game for irresponsible folks with too much time and not willing to pay or do without like most people.

icdg

Indeed. Remember, no discussion of hacking systems...

As for audio encryption... once upon a time (a very long time ago)... the audio was indeed encrypted on Cablelink, IIRC. It may have been for Prem1ere and/or Eurosport (original incarnation). At one stage, Eurosport was encrypted up to 6pm and then in the clear. Don't ask why, these are all very hazy memories from up to fifteen years ago...

As for what the Jerrold boxes use - they don't really seem to encrypt the picture like the NTL ones do - rather it seems to roll/and or disappear completely. Strange.

watty

Strictly the Jerrold boxes don't use encryption at all. It is very primitive scrambling.

If I explained in more detail I'd have to shoot you afterwards..

jmcc

Originally posted by icdg
Indeed. Remember, no discussion of hacking systems...

As for audio encryption... once upon a time (a very long time ago)... the audio was indeed encrypted on Cablelink, IIRC. It may have been for Prem1ere and/or Eurosport (original incarnation). At one stage, Eurosport was encrypted up to 6pm and then in the clear. Don't ask why, these are all very hazy memories from up to fifteen years ago...[

Cablelink used two systems. The one with the wavey lines was only used for a short time. That was the SAVE system which modulated the video signal with a sinewave around 94KHz. It also had sound scrambling which I don't think Cablelink used. A short time later, they switched to the Philips produced Discret system which had previously been a disaster in France. Discret used line delay which gave the picture a jaggedy appearance and also spectrum inverted the audio as scrambling. The problem was that the kit was not reliable. Cryptovision was the replacement and at the time they were also considering Jerrold and VideoCrypt.

As for what the Jerrold boxes use - they don't really seem to encrypt the picture like the NTL ones do - rather it seems to roll/and or disappear completely. Strange.

Not really that strange when you think about it. Jerrold relied on messing with the synch pulses with the effect that the television could not lock up the picture. The Discret, VideoCrypt and Cryptovision solutions relied on messing with the video but leaving the synch pulses alone. Thus you could have a perfectly synched picture in each case but the picture information would be obscured or scrambled.

Regards...jmcc