Signapktic: Sign .apk’s and .zip’s on your Android Device
XDA member Fnorder in collaboration with XDA moderator Stericson, has developed an awesome app for us. The app (Signapktic) allows users to resign update.zip’s and .apk files directly from your Android phone. The app has multiple keys you can choose to sign with and it’s very easy to use for signing your files. It even features a simple file explorer so you can select the .apk or update.zip file you wish to sign.
The app is currently available as free with ad’s and available for download from the market by searching for “signapktic”. The app also requires superuser permissions to run.
To learn more about the app and follow its progress, check out the discussion thread.