You could have downloaded iModSign 4.0 for Mac from our application library for free. IModSign for Mac is categorized as Developer Tools. This free Mac app is an intellectual property of imzdl.
From the developer:
iModSign allows iOS app bundles (.ipa) files to be signed or resigned with digital certificate from Apple for distribution.
This is a very easy to use tool.
Register Your UDID with a Provisioning Profile & Certificate – To Use iModSign! Open all the files that were emailed to you.
You may want to check out more Mac applications, such as PSPP, HexColor or Texpad : LaTeX editor, which might be similar to iModSign.