The hiding-data-in-bogus-text system that Phil referred to is Peter Wayner's Mimic functions, which let you represent data using a Huffman code or context-free-grammar set of productions that matches innocuous text. The examples in the paper used baseball game radio narration (hiding a message "Paul is dead" :-) and political speeches by Mr. Neil Kinnock, the raving Labour Party honcho whose speeches were plagiarized by Joe Biden. (Biden, btw, was a nice guy when he was elected to the Senate at age just-under-30, but he's apparently gone Big Brotherish as he's aged. I'm not bothered by one politician borrowing another's speeches, but stooping to Neil Kinnock's syrupy ranting is a bit much :-) The papers on the mimic functions are in ftp.cs.cornell.ecu, under /pub/wayner/Mimic. There are also a couple of papers on building a highly parallel des-cracker out of content-addressable memory, Until encryption becomes widely used, if yuo want to hide encrypted data, mimic functions or low-bits-of-gifs are good ways to go. Bill Stewart