Resigning Tampered Android APKs
After tampering with a signed apk using tools like smali/baksmali or even apktool here are the steps to rebuild and resign the Android application (from application root):
keytool -genkeypair -alias androiddebugkey -dname 'CN=Android Debug,O=Android,C=US' -keystore /tmp/debug.keystore -keyalg RSA -validity 10000 generate a valid Android debug keypair (Signing in Debug Mode) with password ‘android’ for both the keystore and the keys
rm -rf META-INF if such exists
zip -9 -r out-unaligned.apk . to zip things up
jarsigner -sigalg MD5withRSA -digestalg SHA1 -keystore /tmp/debug.keystore out-unaligned.apk androiddebugkey sign it
zipalign 4 out-unaligned.apk out.apk align it
keytool -printcert -jarfile out.apk check it
adb install -s out.apk install it (you may need to uninstall a previous version of the application in case of certificate errors