https://github.com/codingo/simple-substitution

A CTF challenge for CrikeyCon 2018
https://github.com/codingo/simple-substitution

Last synced: 2 months ago
JSON representation

A CTF challenge for CrikeyCon 2018

• Host: GitHub
• URL: https://github.com/codingo/simple-substitution
• Owner: codingo
• License: gpl-3.0
• Created: 2017-08-28T22:49:00.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2018-02-26T06:59:55.000Z (over 7 years ago)
• Last Synced: 2025-03-25T03:06:09.549Z (2 months ago)
• Language: Python
• Homepage:
• Size: 17.6 KB
• Stars: 3
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
# Simple-Substitution

[![Twitter](https://img.shields.io/badge/twitter-@codingo__-blue.svg)](https://twitter.com/codingo_)

A regular expression CTF challenge for CrikeyCon 2018

# Challenge Description

```

\w*?(p).*([a])[^l]*(l)[a-zA-Z\d]*?(a)({)\w*?(o).+([W-w])(h)[^f]+(f).*

\9\3\2g\5t\7\6ste\1s\4\8e\2d}

LZckWnfFS0NyHyjMpObY0aLi:cVJVcVZkWnfFS0NvlQNiyZa{NVCHJ6zWPPI5KXxGZyUo55ywhR8LzVm4KM92kSfi}fzQHpjMpOb0ii?

```

## Search

```

\w*?(p).*([a])[^l]*(l)[a-zA-Z\d]*?(a)({)\w*?(o).+([W-w])(h)[^f]+(f).*

```

## Replace 

```

\9\3\2g\5t\7\6ste\1s\4\8e\2d}

```

# Flag

```

flag{twostepsahead}

```

# Example Solutions

https://regex101.com/r/l1i0Bs/1

```

# coding=utf8

import re

input_str = "LZckWnfFS0NyHyjMpObY0aLi:cVJVcVZkWnfFS0NvlQNiyZa{NVCHJ6zWPPI5KXxGZyUo55ywhR8LzVm4KM92kSfi}fzQHpjMpOb0ii?"

regex = r"\w*?(p).*([a])[^l]*(l)[a-zA-Z\d]*?(a)({)\w*?(o).+([W-w])(h)[^f]+(f).*"

replace = "\\9\\3\\2g\\5t\\7\\6ste\\1s\\4\\8e\\2d}"

result = re.sub(regex, replace, input_str, 0)

print("Input string: %s" % input_str)

print("Search: %s" % regex)

print("Replace: %s" % replace)

print("-" * 25)

print("Result: %s" % result)

```