Digital watermarking of speech signals for the National Gallery of the Spoken Word

A novel speech watermarking technique has been developed in support of the National Gallery of the Spoken Word (NGSW), a Digital Libraries Initiative, Phase II, sponsored project. Transform encryption coding (TEC) is used to compress and encrypt both the watermark and the coversignal. TEC is employed in combination with a masking algorithm which takes into account the signal energy of the watermark and the coversignal. The process of creating the stegosignal further encrypts the watermark. This dual encryption results in a high level of protection for original materials as the two proper keys (quasi m-arrays) are required to remove each watermark. An application to a sample utterance from the NGSW is presented