Patent Number: 
Section: claims

1. A method of encoding isotopic taggants comprising:identifying a group of M×N distinct isotopic taggants where M and N are integers greater than 1; anddividing said isotopic taggants into M groups of N isotopes each; andassigning one taggant isotope from each of the M groups to correspond to each integer from 0 to N−1 inclusive; andisolating the substance to be tagged and assigning to it an M-digit, base-N serial number; andadding to the substance to be tagged a quantity of each of the M isotopes corresponding to the values of the M digits in the assigned serial number. 2. A binary taggant system comprising:at least a first isotope pair comprising:a first isotope of the first isotope pair capable of functioning as a taggant and representative of the first of two binary values in the absence of the second isotope of the first isotope pair; anda second isotope of the first isotope pair capable of functioning as a taggant and representative of the second of the two binary values in the absence of the first isotope of the first isotope pair;a system adapted to detect presence of each isotope of said first isotope pair and to provide a detected presence of said isotope pair; anda protocol adapted to translate said detected presence into a binary serial number, said protocol yielding:a serial number if one and only one of said first isotope or of said second isotope comprises said detected presence;a determination of contamination if said first isotope and said second isotope comprise said detected presence; and,a determination of loss of information if neither said first isotope nor said second isotope comprises said detected presence. 3. The binary taggant system of claim 2 further comprising:a second isotope pair comprising:a first isotope of the second isotope pair capable of functioning as a taggant and representative of the first of two binary values; anda second isotope of the second isotope pair capable of functioning as a taggant and representative of the second of the two binary values. 4. The binary taggant system of claim 2 further comprising:at least two additional isotope pairs each of said pairs comprising:a first isotope of each additional isotope pair capable of functioning as a taggant and representative of the first of two binary values; anda second isotope of each additional isotope pair capable of functioning as a taggant and representative of the second of the two binary values. 5. A method of tagging a substance potentially subject to contamination including the steps of:assigning to the substance an M-bit binary serial number where M is an integer greater than 1,identifying 2M isotopes and dividing them into M pairs of isotopes,assigning each of the pairs to one of the M bits of said binary serial number,assigning to one isotope of each pair the bit value of 0 and to the other of each pair a bit value of 1,identifying the M isotopes having bit values corresponding to the bit values of said binary serial number,adding to the substance to be tagged a quantity of each of the M isotopes corresponding to the values of the M bits in the assigned serial number. 6. The method of claim 5 further including the steps of:analyzing the tagged substance to detect the presence or absence of each of the 2M isotopes,identifying the corresponding binary serial number if and only if one and only one isotope of each pair is detected to be present, orrejecting as contaminated or degraded any case in which either no isotopes of a pair or two isotopes of a pair are detected to be present.