San Diego-based Verimatrix, which does watermarking and DRM for digital video, has raised a $5 million third round from existing investors, including Mission Ventures. The company has now raised over $13 million, having previously raised $8 million last summer in a round led by Crescendo Ventures, as well as a round for an undisclosed amount in 2005 led by Siemens Venture Capital . Verimatrix’s technology is intended to secure pay-TV networks across the three screens, with particular emphasis on IPTV. Release.