Video Encryption

What is Video Encryption?

Video Encryption is an extremely useful method for the stopping unwanted interception and viewing of any transmitted video or other information, for example from a law enforcement video surveillance being relayed back to a central viewing centre.

The scrambling is the easy part. It is the un-encryption that's hard, but there are several techniques that are available. However, the human eye is very good at, spotting distortions in pictures due to poor video decoding or poor choice of video scrambling hardware. Therefore, it is very important to choose the right hardware or else your video transmissions may be un-secure or your decoded video may not be watchable.

Some of the more popular techniques are detailed below:

Line Inversion:

Method: Whole or parts of the signal scan lines are inverted. Advantages: Simple, cheap video encryption. Disadvantages: Poor video decrypting quality, low obscurity, low security.

Sync Suppression:

Method: Hide/remove the horizontal/vertical line syncs.

Advantages: Provides a low cost solution to Encryption and provides good quality video decoding.

Disadvantages: This method is incompatible with some distribution equipment. Obscurity (i.e. how easy it is to visually decipher the image) is dependant on video content.

Line Shuffle:

Method: Each signal line is re-ordered on the screen.

Advantages: Provides a compatible video signal, a reasonable amount of obscurity, good decode quality.

Disadvantages: Requires a lot of digital storage space. There are potential issues with video stability. Less secure than the cut and rotate encryption method (see below)

Cut & Rotate:

Scrambling Method: Each scan line is cut into pieces and re-assembled in a different order.

Advantages: Provides a compatible video signal, gives an excellent amount of obscurity, as well as good decode quality and stability.

Disadvantages: Can have complex timing control and requires specialized scrambling equipment

The cut and rotate video encryption method is probably the best way of achieving reliable and good quality video encryption, an example of a good implementation of this system is in the Viewlock II

Implementing vice scrambling

The video scrambling hardware, in particular the decoder should function correctly even if there is a noisy (for example having what are commonly known as 'snow' on the screen. 'Snow' is when there are flecks on your TV screen, often seen in poor reception areas) or unstable signal. If the link to the encrypted signal should stop working then this should not be a problem. The link between the video encoder and video decoder should be regained and the decryption quickly continued.

The very nature of security camera systems is that they are often outdoors as so must be able to withstand the rigours of the weather. The video encryption hardware should be stable under or protected from the effects of rain, sunlight, extreme heat and cold. It should not be damaged if there is a power spike in the supply. In these systems the video encoder emits a wireless signal to the video decoder unit before it is viewed, it obviously must be the case that the very act of broadcasting the signal does not effect the video encoding hardware and likewise the video encoding hardware should not effect the radio transmitter.

The most important item is that the video scrambling system should be secure, else why bother? It is amazing how some encryption methods can easily be cracked. For example certain cable television stations 'encrypt' their channel broadcasts via a relatively un complex method, which can easily be decoded using a number of cheap bits of electronics from radio shack. That would obviously be illegal! The cable TV's method of encryption is very crude, they usually just dynamically alter the vertical sync signal so that your TV cannot get a proper lock on it and so it scrolls randomly.

The other extreme is to scramble the transmitted video signal too much so that it is costly both in equipment and time to the video at the receiver. Remember that this is a 'live' video scrambling broadcast followed by a 'live' video decryption display. ANY electronics can be copied, given enough money and time, but making this process as hard as possible is of benefit as it at least delays the time when illegal copies will be available.

Finally and most obviously each user must have a unique encryption key so that other users of the system cannot view the transmitted video by accident or purpose without the key owners knowledge. The total number of possible user keys must be such that it is highly unlikely for someone to guess the correct key.

Ovation Systems are specialists in the design and manufacture of high quality covert video surveillance equipment. Products include the Viewlock II video encryption system.

---

How to Change, Upgade or Remove an IDE Hard Drive

Hard drives - Hard drives are a little more complicated.... Read More

A Look at Laser Toners

Laser toner is the ink for laser printers. It is... Read More

Learn to Find Cheap Laptop Computers on the Internet

Cheap laptop computers are coming to a store near you.... Read More

What is Blu-Ray DVD

Video technology has increased significantly over the past years, and... Read More

How to Avoid Getting Ripped-Off When You Purchase A New Printer

It's no big secret that printer companies like HP and... Read More

Adding Serial Ports to a Computer with Only USB Ports

So you bought a new computer but you don't have... Read More

DVD ROMs

DVD CD ROMs have become predominantly the most used CD... Read More

Emergency Response VSAT Internet Communications

As 2005 begins, there are a number of products on... Read More

Expansion Cards Part 2: AGP

Expansion Cards Part 2: AGPThe first in this series of... Read More

Throw Away The Fax Machine ? A Guide To Online Fax

Have you ever felt like throwing the fax machine out... Read More

Pixel Disruption To Cause Nausea From User of Computer Screen

As we study the issues associated with teaching kids in... Read More

Review of Popular Wireless Headphones

Just about everyone would I agree, I think, that wires... Read More

Where does technology come from?

Ever wonder where all the cool gadgets come from? Ever... Read More

How to Check Your IP

So you need to check your IP address, for whatever... Read More

RAM - What is It & Why You Need Plenty

This is the first article in the Understanding Your Computer... Read More

DVD Recorders: Getting Started

IMO, these sd work 'like a VCR' as far as... Read More

RAID Disk Recovery

RAID is short for Redundant Array of Independent (or Inexpensive)... Read More

Where Can I Find The Best Case Mods Online and Save Money?

Are you captivated by the stunning Case Mods you've seen... Read More

War of the Disks: A Close-in Analysis of the Hard Disk Drive vs. the Solid State Disk

Much has been written about solid state disks (SSDs) becoming... Read More

The Printer Cartridge Game

Think you got a great deal on a printer? Like... Read More

Small Computers

Today, small form factor computers demolish the myth that bigger... Read More

Can I Use My Old Ink With My New Printer?

The quick answer is...yes and no.Consider this. How many printer... Read More

Laptop and Notebook Theft Prevention

Laptops or Notebook computers are an expensive personal and business... Read More

Used Laptop Computer: Your Quick Purchase Inspection Guide ? Part 4

Used laptop computers are everywhere these days. How can you... Read More

Learn About The Three Basic Types Of Computer Mouse

1) Mechanical: This is a type of computer mouse that... Read More

Discover Everything About Wholesale Bar Code Reader And Software!

It is a given fact that buying wholesale would make... Read More

What Can You Do With A Mac Mini?

If you have not seen the newest addition to the... Read More

Motherboard Basics

A recent Tech Tip covered the basics of selecting a... Read More

How to Get the Case Off Your PC!

This is the first step to servicing, upgrading or removing... Read More

Computer Cooling Hardware

PC cooling systems are one of the hottest - and... Read More

The Road Ahead

We live in an area that has begun to... Read More

Survey of Both Past and Modern Printers

Printers are on-line devices initially categorised as being either impact... Read More

Just The Fax, M?am

For years, I smugly prided myself as a non-fax machine... Read More