Patent ID: 8745402

Claim:
A method, said method comprising: generating a unique code for each of a plurality of users using a plurality of symbols; generating a plurality of inner codes representing said plurality of symbols, wherein said second generating act further comprises generating a string of first symbols followed by second symbols, and further wherein said first symbols are all ones and said second symbols are all negative ones, wherein there is an equal quantity of said first symbols and said second symbols in each generated inner code, and further wherein if a length of said first symbols followed by said second symbols is less than a predetermined length of each of said plurality of inner codes, then said first symbols followed by said second symbols are repeated until said code length is filled, wherein said plurality of inner codes representing said plurality of symbols is an exponential orthogonal code; substituting said plurality of inner codes into said unique code for each of said plurality of users; permuting said code resulting from said substitution to produce a codeword for each of said plurality of users; and embedding said codeword into digital content.