Compressed archive format created by Smith Micro StuffIt 7.0 or later; introduced in 2002, StuffIt X uses Smith Micro's exclusive ATOM compression technology and offers up to 20% more compression than standard Stuffit (.SIT) archives.
The SITX format supports long-filenames, preservation of UNIX (ie: OS X) and Windows file permissions, and error correction, which fixes data transmission errors. It may also include 512-bit encryption for file security purposes. Version 9 and later allows 15-30% compression of JPEG images.
NOTE: StuffIt was previously developed by Allume Systems (formerly Aladdin Systems), but is now developed and distributed by Smith Micro.