Unknown Plaintext Attack250 points

Released at: 2021/03/11
$ php split_flag.php
$ zip -e flag.zip flag[1-7].txt
Enter password:
Verify password:
  adding: flag1.txt (stored 0%)
  adding: flag2.txt (stored 0%)
  adding: flag3.txt (stored 0%)
  adding: flag4.txt (stored 0%)
  adding: flag5.txt (stored 0%)
  adding: flag6.txt (stored 0%)
  adding: flag7.txt (stored 0%)
$ zip -h
Copyright (c) 1990-2008 Info-ZIP - Type 'zip "-L"' for software license.
Zip 3.0 (July 5th 2008). Usage:
 :
$ /lib/x86_64-linux-gnu/libc.so.6
GNU C Library (Ubuntu GLIBC 2.32-0ubuntu3) release release version 2.32.
Copyright (C) 2020 Free Software Foundation, Inc.
 :