It includes drawing tools and digital watermarking for embedding copyright information, and new special effects, such as bevel, weave, and blinds.

CNN: Top 10 hot graphics tools

The team made detailed comparisons of the watermarked and unwatermarked versions of the first song, and then analysed the two watermarked songs using their knowledge of past techniques for watermarking.

ECONOMIST: Digital watermarks

Whether or not the researchers met acceptable quality standards, what bodes ill for digital watermarking is that Dr Felten and his colleagues got such a long way with only three test files per technology.

ECONOMIST: Digital watermarks

The watermarking is not just a fancy signature.

ECONOMIST: Artificial lifeforms

Watermarking music may turn out to matter more.

ECONOMIST: In the picture

Watermarking has its limitations.

ECONOMIST: In the picture