Governments have always been plagued by document leaks. Now Sun Microsystems of Mountain View, California, has come up with a way to identify the culprits (EP 798 619).
The technique can identify the source of the document if it has been photocopied, or scanned with optical character recognition. It even works if the document has been retyped.
Each authorised recipient of the document is assigned a number in binary code. Sun's coding system then analyses the text and makes minor changes to each copy, such as leaving out a comma. These changes incorporate the unique code in the textwithout altering the meaning.
If someone leaks a copy, Sun's decoder compares the leaked document with the master, logs the differences and works out which of the authorised copies has been leaked.
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