[APP][ROOT] Zip signer! 02:13

Here is an App for signing Zip, Apk onboard your Android devices. Results are also automatically zip-aligned. Choice of keys: media, platform, shared, testkey -- or use auto-key selection modes.

Similar to jarsigner and signapk, this app can be used to sign update zip files, APK, or JAR files using one of the four built-in certificates.

This app runs without root privileges, but you'll most likely need root to do something with the results. 

Doing some moddifications to your apk or have to add something to a flashable zip file? you will need to sign it and this is the most easiest way to do it.