Conclusion Developed new techniques and tools to find hidden messages on the Internet: Stegdetect automatically detects steganographic content. Crawl is an efficient web crawler that saves JPEG images. Stegbreak mounts dictionary attacks against images. Disconcert is a distributed computing framework that assigns jobs to a cluster of workstations. Software available under BSD-license: Stegbreak and disconcert will be released soon. http://www.citi.umich.edu/u/provos/ Outguess 0.2 is undetectable by these techniques: http://www.outguess.org/