ELECTRONIC WATERMARK EMBEDDING AND EXTRACTION

摘要

PROBLEM TO BE SOLVED: To provide an electronic watermark that can realize high concealment and has sufficient immunity to high efficiency compression coding and Jitter attack or the like. SOLUTION: A band split section 42 divides a frequency band of original sound data into a low frequency band component and a plurality of intermediate frequency band components (S104). A spread section 44 multiplies a PN sequence with the low frequency band component to generate a spread signal (S106). An MDCT transform section 46 applies MDCT transform to the spread signal to introduce an MDCT coefficient (S108). An embedding section 48 embeds watermark bits to the MDCT coefficient (S110). An IMDCT transform section 50 applies IMDCT transform to the MDCT coefficient to which the watermark bits are embedded to produce an embedded spread signal (step S112). A band component restoration section 52 multiplies a PN sequence with the embedded spread signal to produce an embedded low frequency band component (S114). A band composite section 54 composites the embedded low frequency band component with a plurality of the intermediate frequency band components to produce embedded sound data (S116).