Copycoder
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The Copycoder is a flat optical panel which has the property of scrambling text which is viewed or photocopied through it. Equally, it will work in reverse and will descramble text previously created when using it. It was invented in 1997 in Great Britain by Stephen Ostler. Originally, he developed it for office use, intending it as a quick encryption tool for processing printed A4 pages and sending faxes securely. Today, however, it has found its main role as a toy which enables children and young people to exchange 'secret messages' quickly and simply.
The Copycoder works by optically splitting up the page into strips and laterally inverting each strip. This task is accomplished by using cylindrical lenses of depth twice their focal length and stacking them side by side. Such strips have been called 'refractive mirrors'. The strips usually are arranged to point at an angle of 40 degrees to the perpendicular. This means that the strips of image are not only laterally inverted, but are rotated too (actually by twice the 40 degree angle). This provides a more intense scrambling effect.
In use, the Copycoder is placed directly on top of the text which is to be scrambled and the resulting view can then be stored by photocopying or scanning. The resulting pattern is totally illegible, but if another Copycoder of similar characteristic is placed on top of this pattern, once again the original text is reconstructed into perfect legibility.
Software has now been written to perform the scrambling function. This means creation of the scrambled patterns from text can be performed with no need to use either a Copycoder or a photocopier. However a Copycoder is still required to do the descrambling.
It has been been found that a relationship exists between the optimal width of the cylindrical lens elements and the size of the text characters to be scrambled; i.e. the larger the font size, the greater the required width of the lens elements. However, this is not too critical and the font size can vary by a factor of more than two with good scrambling still being obtained.
Copycoders have been made with various configurations of encoding strips. For example, different widths of strip can be stacked together (standing for a binary number), and sets of such strips set within rotatable hexagonal elements. This provides individual key coding for each Copycoder. Further refinements to this technique have also been developed.
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