What is video Encryption?
video encryption is a very useful method for stopping unwanted interception and viewing of all videos submitted or other information, for example, from a video surveillance system of law to be transmitted to a central display center.
Scrambling is the easy part. It 's the non-encryption that difficult, but there are several available techniques. However, the human eye is very good, spottingimage distortion due to poor video decoding or poor choice of video scrambling hardware then. It 's very important to choose the right hardware or watchable video broadcasts are not safe or the video can not be decoded.
Some of the most common techniques are listed below:
Line Reversal:
Method: All or part of the signal scan lines are reversed.
Advantages: Simple, cheap videoEncryption.
Disadvantages: Poor quality video decoding, low dark, low-security.
Sync Suppression:
Method: Remove skin, / synchronizes the horizontal and vertical.
Advantages: It provides an economical solution for encryption and decryption of video provides a good quality.
Disadvantages: This method is incompatible with some distribution equipment. Darkness (ie how easy it is to decipher the visual image) depends on the video content.
LineShuffle:
Method: Each signal line is re-arranged on the screen.
Advantages: a video signal compatible with a reasonable amount of obscurity, good decode quality offers.
Disadvantages: Requires a lot of digital space. There are potential problems with the stability of the video. Less sure of the cut and rotate encryption method (see below)
Cut & Rotate:
Scrambling Method: Each scan line is cut in pieces and reassembled in another. Bestellen
Advantages: Provides a compatible video signal, is an excellent amount of obscurity, as well as good decode quality and stability a.
Disadvantages: It can control the timing requires special equipment and complex scrambling
The cutting and rolling video encryption method is probably the best way to get reliable, high quality video encoding, an example of correct application of this system is Viewlock II
Implement loadScrambling
The video scrambling hardware, in particular, the decoder should function correctly even if it is a strong (for example, what is commonly known as "Snow on the screen." Snow "when it spots on the TV screen, often to see the poor reception areas) or unstable signal. If the connection should be encrypted signal to stop working, this should not be a problem. between the video encoder and video decoder should be connected, and again theDecryption away quickly.
The nature of the systems of surveillance cameras is that they often are in the open air, as has been maintained to be able to vagaries of weather. The video encoding hardware should be stable under or protected from the effects of rain, sun, extreme heat and cold. It must not be damaged if it is a peak power in the supply chain. In these systems the video encoder is a wireless signal to the central decoder video before it appears,obviously must be the case that the act of spreading the signal has no effect on hardware video encoding and the hardware video encoding should not make the radio transmitter.
The most important point is that the video coding system should be safe, or what? It 'amazing how some encryption methods can be cracked easily. For example, some cable TV channels 'encrypt' their channel broadcasts via a relatively non-complexMethod that can be easily deciphered a number of cheap bits of electronics from Radio Shack. That would be illegal, of course! The encryption method of cable TV is very rough, but usually just dynamically change the vertical sync signal, so that the TV for no real obstacle, and so it rolls at random.
The other extreme is the encoding of the video signal output too, so is the recipient of expensive both in equipment and time for the video to Rememberthat this is a live video scrambling "display broadcast, followed by a live video decoding." any mail could be copied, because enough money and time, but makes this process as hard as possible to be helpful, because at least delay the when illegal copies will be available.
Finally, and most obviously, each user has a unique key that other users of the system, but can not send videos by accident or purpose without the key ownerKnowledge. The total number of possible user keys must be such that it is highly unlikely that anyone has to guess the right key.
ไม่มีความคิดเห็น:
แสดงความคิดเห็น