$ python paddingzip.py -h
usage: paddingzip.py [-h] -i INPUT_FILENAME -o OUTPUT_FILENAME [-p PREPEND] [-a APPEND]

A tool that you can craft a zip file that contains the padding characters between the file content

optional arguments:
  -h, --help            show this help message and exit
  -i INPUT_FILENAME, --input INPUT_FILENAME
  -o OUTPUT_FILENAME, --output OUTPUT_FILENAME
  -p PREPEND, --prepend PREPEND
                        the characters that you want to prepend to the file beginning
  -a APPEND, --append APPEND
                        the characters that you want to append to the file

python paddingzip.py -i original.jar -o modify.jar --prepend "this prepend to the start" --append "this append to the end"

f $ cat f a.zip > b.zip $ zip -F b.zip --out c.zip">

$ echo -n "prepend" > f
$ cat f a.zip > b.zip
$ zip -F b.zip --out c.zip