Miscellaneous CTF Tools

When to Use

Load this skill when:

• Solving programming or algorithm challenges

• Decoding esoteric languages (Brainfuck, Malbolge, etc.)

• Scanning QR codes or barcodes

• Analyzing audio/video files

• Working with unconventional challenge types

Programming Challenges

Fast Input Parsing

#!/usr/bin/env python3 """Template for fast I/O in programming challenges""" import sys

def fast_input(): """Read all input at once (faster than input())""" return sys.stdin.read().strip().split('\n')

def solve(): """Main solution""" lines = fast_input() n = int(lines[0])

for i in range(1, n + 1):
    # Process each line
    data = list(map(int, lines[i].split()))
    result = process(data)
    print(result)

def process(data): """Process logic here""" return sum(data)

if name == "main": solve()

Common Algorithms

Binary Search

def binary_search(arr, target): left, right = 0, len(arr) - 1 while left <= right: mid = (left + right) // 2 if arr[mid] == target: return mid elif arr[mid] < target: left = mid + 1 else: right = mid - 1 return -1

GCD (Greatest Common Divisor)

def gcd(a, b): while b: a, b = b, a % b return a

LCM (Least Common Multiple)

def lcm(a, b): return abs(a * b) // gcd(a, b)

Prime Check

def is_prime(n): if n < 2: return False if n == 2: return True if n % 2 == 0: return False for i in range(3, int(n**0.5) + 1, 2): if n % i == 0: return False return True

Factorial with memoization

from functools import lru_cache

@lru_cache(maxsize=None) def factorial(n): if n <= 1: return 1 return n * factorial(n - 1)

Esoteric Languages

Brainfuck Interpreter

#!/usr/bin/env python3 """Brainfuck interpreter"""

def brainfuck(code, input_data=""): """Execute Brainfuck code""" # Initialize tape = [0] * 30000 ptr = 0 code_ptr = 0 output = [] input_ptr = 0

# Match brackets
brackets = {}
stack = []
for i, cmd in enumerate(code):
    if cmd == '[':
        stack.append(i)
    elif cmd == ']':
        if stack:
            left = stack.pop()
            brackets[left] = i
            brackets[i] = left

# Execute
while code_ptr < len(code):
    cmd = code[code_ptr]
    
    if cmd == '>':
        ptr += 1
    elif cmd == '<':
        ptr -= 1
    elif cmd == '+':
        tape[ptr] = (tape[ptr] + 1) % 256
    elif cmd == '-':
        tape[ptr] = (tape[ptr] - 1) % 256
    elif cmd == '.':
        output.append(chr(tape[ptr]))
    elif cmd == ',':
        if input_ptr < len(input_data):
            tape[ptr] = ord(input_data[input_ptr])
            input_ptr += 1
    elif cmd == '[':
        if tape[ptr] == 0:
            code_ptr = brackets[code_ptr]
    elif cmd == ']':
        if tape[ptr] != 0:
            code_ptr = brackets[code_ptr]
    
    code_ptr += 1

return ''.join(output)

Example

code = "++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++." print(brainfuck(code)) # Output: "Hello World!\n"

Common Esoteric Language Patterns

Language Detection Tool

Brainfuck +-<>[]., characters only esolang/bf_decode.py

Malbolge Base-85 printable ASCII Online interpreter

Whitespace Only spaces, tabs, newlines Online interpreter

JSFuck !+ characters only Browser console

Ook! Ook. Ook? Ook!

Online interpreter

Piet Colorful bitmap image npiet compiler

Online Interpreters

Try44 - Multi-language online interpreter

https://tio.run/

Esoteric.codes

https://esoteric.codes/

QR Codes and Barcodes

Scan QR Codes

Install zbar tools

sudo apt install zbar-tools

Scan single QR code

zbarimg qrcode.png

Scan multiple QR codes

zbarimg qr1.png qr2.png qr3.png

Output to file

zbarimg qrcode.png > output.txt

Scan All QR Codes in Directory

#!/bin/bash

Scan all images in directory for QR/barcodes

for file in *.png *.jpg *.jpeg; do if [ -f "$file" ]; then echo "=== $file ===" zbarimg "$file" 2>/dev/null || echo "No code found" echo fi done

Generate QR Code

Install qrencode

sudo apt install qrencode

Generate QR code

qrencode -o output.png "Your text here"

Generate with error correction

qrencode -l H -o output.png "Your text here"

Levels: L (7%), M (15%), Q (25%), H (30%)

Python QR Code

from PIL import Image import subprocess

def scan_qr(image_path): """Scan QR code from image""" result = subprocess.run( ['zbarimg', '--quiet', '--raw', image_path], capture_output=True, text=True ) return result.stdout.strip()

Usage

data = scan_qr('qrcode.png') print(f"QR Code data: {data}")

Audio and Video Analysis

Audio Spectrogram

Generate spectrogram with Sox

sox audio.wav -n spectrogram -o spectrogram.png

With higher resolution

sox audio.wav -n spectrogram -x 3000 -y 513 -z 120 -w Kaiser -o spectrogram.png

Extract specific frequency range

sox audio.wav -n spectrogram -o spec.png trim 0 10 # First 10 seconds

Audio Metadata

Extract metadata

exiftool audio.mp3 ffprobe audio.mp3

Extract hidden data from LSB

python3 helpers/audio_lsb.py audio.wav

Video Frame Extraction

Extract all frames

ffmpeg -i video.mp4 frames/frame_%04d.png

Extract every 10th frame

ffmpeg -i video.mp4 -vf "select='not(mod(n,10))'" -vsync 0 frames/frame_%04d.png

Extract frame at specific time

ffmpeg -i video.mp4 -ss 00:01:30 -vframes 1 frame.png

DTMF Tone Decoding

Install multimon-ng

sudo apt install multimon-ng

Decode DTMF tones from audio

sox audio.wav -t raw -r 22050 -e signed -b 16 -c 1 - | multimon-ng -t raw -a DTMF /dev/stdin

Encoding and Decoding

Common Encodings

import base64 import codecs

Base64

data = base64.b64decode('SGVsbG8gV29ybGQ=')

Base32

data = base64.b32decode('JBSWY3DPEBLW64TMMQ======')

Base85

data = base64.b85decode(b'BOu!rD]j7BEbo7')

Hex

data = bytes.fromhex('48656c6c6f')

ROT13

data = codecs.decode('Uryyb Jbeyq', 'rot_13')

URL encoding

from urllib.parse import unquote data = unquote('Hello%20World')

Multi-Layer Decoding

def auto_decode(data): """Try common decodings recursively""" import base64 import binascii

if isinstance(data, bytes):
    try:
        data = data.decode('utf-8')
    except:
        return data

# Try base64
try:
    decoded = base64.b64decode(data)
    if decoded != data.encode():
        print("[+] Base64 decoded")
        return auto_decode(decoded)
except:
    pass

# Try hex
try:
    decoded = bytes.fromhex(data)
    print("[+] Hex decoded")
    return auto_decode(decoded)
except:
    pass

return data

Usage

result = auto_decode("NGE2MTY3N2I2MjYxNzM2NTM2MzQ1Zjc0Njg2OTcyNzQ3OTVmNzQ3Nzc2") print(result)

Quick Reference

Challenge Type Tool Command

Brainfuck Python python3 esolang/bf_decode.py code.bf

QR Code zbar zbarimg qrcode.png

Barcode zbar zbarimg barcode.jpg

Spectrogram sox sox audio.wav -n spectrogram -o spec.png

DTMF multimon-ng multimon-ng -a DTMF audio.wav

Video frames ffmpeg ffmpeg -i video.mp4 frames/frame_%04d.png

Base64 base64 base64 -d <<< "SGVsbG8="

Hex xxd xxd -r -p hex.txt output.bin

Bundled Resources

Programming

• programming/fast_parse.py

• Fast I/O template for competitive programming

• programming/algorithms.py

• Common algorithms (GCD, LCM, primes)

Esoteric Languages

• esolang/bf_decode.py

• Brainfuck interpreter

• esolang/malbolge_helper.md

• Malbolge reference

QR and Barcodes

• qr_barcodes/qr_scan_all.sh

• Batch QR code scanner

• qr_barcodes/qr_generate.sh

• QR code generator wrapper

Audio and Video

• audio_video/spectrogram.sh

• Generate audio spectrogram

• audio_video/extract_frames.sh

• Extract video frames

• audio_video/audio_lsb.py

• Audio LSB steganography

External Tools

Esoteric language interpreters

pip install bf # Brainfuck

QR/Barcode tools

sudo apt install zbar-tools qrencode

Audio/Video tools

sudo apt install sox ffmpeg multimon-ng audacity

Python libraries

pip install qrcode pillow pydub

Keywords

miscellaneous, misc, programming, algorithms, esoteric languages, brainfuck, esolang, QR code, barcode, zbar, audio analysis, spectrogram, DTMF, video analysis, frame extraction, ffmpeg, sox, encoding, decoding, base64, hex, multi-layer decoding, competitive programming