Abstract: A method for storing and coding information which utilizes mixtures of metal nanoclusters with dyes and other Raman-active substances is disclosed. A method for reading and decoding the stored information by measuring the Raman spectra is also disclosed. To code and store information, a plurality of dots or markers, each consisting of a mixture of two or more Raman-active substances taken in different proportions, is applied on a on object. The number of substances in the mixture and the relative quantities of each substance in the mixture carry the information to coded by each dot. By scanning a sequence of dots on the object, information stored in the sequence can be read and decrypted. Surface enhanced Raman scattering associated with metal nanoclusters and large Raman cross section of colored Raman-active substances make it more feasible to detect the Raman signal from a single dot of a small size (up to the diffraction limit) on the millisecond time scale.