Rolling Code Inversion

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Fish911

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A rolling code inversion...anyone know anything about it?
Any help in the area would be great.
 

phyberoptics

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This is a method of encryption which uses encryption "keys" whereby the keys can be changed (rolled) which would make it impossible (improbable) to decode.

It would be like having a set of keys cut for a lock, and finding the lock has been changed when you try to open it...
 

mancow

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Not really. It's a rolling audio split point. The frequency at which the audio is inverted on each side of it moves so a single split point simple inverter is ineffective.

Also, it can be broken. I don't know how it was done but it worked.




phyberoptics said:
This is a method of encryption which uses encryption "keys" whereby the keys can be changed (rolled) which would make it impossible (improbable) to decode.

It would be like having a set of keys cut for a lock, and finding the lock has been changed when you try to open it...
 

DaveH

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mancow said:
Not really. It's a rolling audio split point. The frequency at which the audio is inverted on each side of it moves so a single split point simple inverter is ineffective.

Also, it can be broken. I don't know how it was done but it worked.

That's Variable Split-Band Inversion (VSB or VSBI). Not all rolling-code uses
this technique.

Dave
 

Jammin_Jay

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Question, Fish, do u here a squawk at the beginning of the transmission like a databurst, then a bunch of ticks in between the garbled (or inverted talk)? I have know a couple of police depts to use rolling-code inversion and then switch to normal baseband inversion because of the audio trouble involved with it, the actually oscillating of the invert-frequency causes some discrepencies sometimes, which the depts would tell the techs when they would "switch over" or "go to security" as they called it. Inversion is an inexpensive and easy way to implement into a radio because agencies donot have to buy a whole new complete radio system like digital. The inversion modules are attached inside the radio, saving big money but not offereing the best encryption
 
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