We do not have a download file for the latest version (4.2.8.540), but you can try downloading it from the developer's site
Download version 1.1.0.37441 from Mac Informer
Version: 1.1.0.37441
Date update: Feb 26, 2013
File name: asperacrypt-1.1.0.37441-mac-intel-10.5.dmg
Size: 13.4 MB