Patent ID: 7991751

Claim:
A processor-implemented method for detecting distribution of an information item included within passing information sequences obtained from a digital medium, said information item comprising any one of a specified set of prestored information items whose distribution it is desired to control, comprising: transforming each item of said set of prestored information items whose distribution it is desired to control from a first representation format into a respective format facilitating a first comparison, said first comparison being fast in relation to a second relatively slower textual comparison, in accordance with a predetermined transformation format, said predetermined transformation format being preservative of meaning; transforming passing information sequences, obtained from said digital medium, into said format facilitating said first relatively fast comparison in accordance with said transformation format; determining the presence of one or more of said prestored information items within said transformed information sequence, said determining comprising: comparing respective information sequences in said format facilitating said relatively fast comparison with said prestored information items in said format facilitating said relatively fast comparison; when a match is found between said formats facilitating said relatively fast comparison then carrying out said second relatively slower textual comparison between said respective prestored information item in said first representation format and a respective information sequence obtained from said digital medium, and when a match is found using said second relatively slower textual comparison, applying a policy to control distribution of said respective information sequence.