Abstract
Digital watermarking has become an accepted technology
for enabling multimedia protection schemes. While most efforts
concentrate on user authentication, recently interest in data
authentication to ensure data integrity has been increasing.
Existing concepts address mainly image data. Depending on the
necessary security level and the sensitivity to detect changes in
the media, we differentiate between fragile, semifragile, and
content-fragile watermarking approaches for media authentication.
Furthermore, invertible watermarking schemes exist while each bit
change can be recognized by the watermark which can be extracted
and the original data can be reproduced for high-security
applications. Later approaches can be extended with cryptographic
approaches like digital signatures. As we see from the literature,
only few audio approaches exist and the audio domain requires
additional strategies for time flow protection and
resynchronization. To allow different security levels, we have to
identify relevant audio features that can be used to determine
content manipulations. Furthermore, in the field of invertible
schemes, there are a bunch of publications for image and video
data but no approaches for digital audio to ensure data
authentication for high-security applications. In this paper, we
introduce and evaluate two watermarking algorithms for digital
audio data, addressing content integrity protection. In our first
approach, we discuss possible features for a content-fragile
watermarking scheme to allow several postproduction
modifications. The second approach is designed for high-security
applications to detect each bit change and reconstruct the
original audio by introducing an invertible audio watermarking
concept. Based on the invertible audio scheme, we combine digital
signature schemes and digital watermarking to provide a public
verifiable data authentication and a reproduction of the
original, protected with a secret key.