Prosecutors say the file was created, maintained and possessed by Schultz and assert that documents in the file are "inconsistent" with statements made by Schultz and Curley to a grand jury.
This packet of data (usually about four kilobytes of code) is then embedded within the file, and a digital watermark is inserted into the newly created space left behind by the compression process.
The deal shows how far Skype has come since it was launched in 2003 by Niklas Zennstrom and Janus Friis, two men who had created a file-sharing technology called Kazaa that became widely associated with music piracy.