[Editor: When I heard about the creator of BitTorrent getting into steganography, I was admittedly intrigued. So the first thing I did was ping some of my former coworkers at Digimarc to get their take. Here’s what our local experts in steganography had to say.]
The recent revelations of the NSA’s activities have many people rightfully concerned, especially in our progressive leaning corner of the world, but after a year of work, the creator of BitTorrent has a released a tool that he hopes will level the playing field through the use of Steganography (the ability to hide information in plain-sight).
Brad Cohen announced DissidentX at the Real World Crypto conference in New York early this year, with the goal of providing a tool to those who risk their lives for the simple act of sharing divergent views under repressive regimes. The tool accomplishes this by hiding information inside content, such as pictures, video, audio, or even a blog post such as this.
It is not a new idea, the earliest use of steganography can be traced back to the Spartans in 440 BC, but the techniques have certainly evolved for the digital age. By subtly changing pixels, audio samples or replacing words in a document, the goal is that the repressive regime with their content filtering tools only see the content on the surface, such as pictures from a family vacation, or an inconsequential email, etc. The true message is hidden from view.
The underlying technology is similar to digital watermarking. The primary difference is digital watermarking creates messages that are imperceptible to the casual observer but easily detected in a wide variety of environments. We are already awash in digital watermarks in our everyday lives as most television and radio stations rely on watermarks to determine ratings. The technology is increasingly being used by publishers to displace QR codes or even speed checkout at the grocery store.
Unfortunately while Cohen’s zeal for the space is encouraging, the tool does not break new ground and suffers from many of the shortcomings of stenographic tools (PDF) from a decade ago. The tool comes with a simple example implementation that adds spaces at the end of a line to encode the message. Effective yes, but easily discovered by an interested observer. The real value is in how the tool uses existing cryptographic constructs to encode the message, enabling multiple decryption keys to be used with some being decoys.
To Cohen’s credit, he has been clear about the state of the tool and is encouraging others to build on what is provided to inspire innovation and raise the importance of facilitating open and free communication. Both the steganographic and digital watermarking community (which has deep roots in the Portland startup scene) will only benefit with this renewed interest in the field.
Tony Rodriguez joined Digimarc in 1996 and currently serves as Chief Technology Officer. Rodriguez has 25 years experience in computer science and image processing research and development. With deep roots in Oregon and Washington, Rodriguez has had the opportunity to build and collaborate with wonderfully talented teams, resulting in demonstrated financial performance for investors and over a hundred issued patents and publications in the area of Digital Watermarking.
Before joining Digimarc, Rodriguez worked at the Intel Architecture Labs as a senior software engineer, focused on video segmentation and streaming technologies. Prior to that, Rodriguez held a variety of engineering and research positions at Raytheon, Jet Propulsion Laboratory (JPL) and IBM.
Tomas Filler does research and development in areas related to watermarking and steganography at Digimarc Corporation. Before joining Digimarc, Tomas spent many years at State University of New York at Binghamton working on various aspects of steganographic security of digital images. Many of his algorithms were tested in public competitions like Break Our Steganographic System, which he co-organized in 2010. Tomas actively participates in steganographic community by serving as a reviewer and as a member of many program committees. In his free time, Tomas loves ballroom dancing.
(Image courtesy Eddie Codel. Used under Creative Commons.)