Cryptography Guide

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🛠️ Cryptographic Tools and Software ​

🔍 Analysis Tools ​

CyberChef - The Cyber Swiss Army Knife ​

What It Does: Web-based encoding/decoding/analysis/conversion tool

bash
# Common CyberChef "recipes":
Base64 > XOR > ROT13
Magic Function for auto-detection
String manipulation and analysis

🔥 Pro Tip: Save your favorite recipes for quick access!

Ghidra ​

What It Does: Software reverse engineering framework

bash
# Basic Usage:
ghidra_9.X/ghidraRun
New Project > Import Binary > Analyze

🎓 Learning Resources: NSA's official Ghidra course materials

IDA Pro/Free ​

What It Does: Interactive disassembler for binary analysis

  • Powerful debugging capabilities
  • Multi-platform support
  • Extensible with plugins
  • Python scripting support

🌐 Network Security ​

Wireshark ​

What It Does: Network protocol analyzer

bash
# Useful capture filters:
tcp port 443
host 192.168.1.1
!(arp or dns)

🔐 Security Tip: Always capture on a secure network you own!

Burp Suite ​

Features:

  • Proxy intercepting
  • Scanner
  • Repeater
  • Intruder
  • Decoder
  • Comparer

🔓 Code Breaking ​

HashCat ​

bash
# Common attack modes:
hashcat -a 0 -m 0 hash.txt wordlist.txt        # Dictionary
hashcat -a 3 -m 0 hash.txt ?a?a?a?a?a?a        # Brute force
hashcat -a 1 -m 0 hash.txt wordlist1.txt wordlist2.txt  # Combinator

John the Ripper ​

bash
# Basic usage:
john --wordlist=passwords.txt --format=raw-md5 hashes.txt
john --show --format=raw-md5 hashes.txt

🔒 Encryption Tools ​

GPG (GNU Privacy Guard) ​

bash
# Key management:
gpg --gen-key                     # Generate new key pair
gpg --encrypt --recipient user@example.com file.txt
gpg --decrypt file.txt.gpg

VeraCrypt ​

  • Create encrypted containers
  • Full disk encryption
  • Hidden volumes
  • Plausible deniability

🔬 Forensics ​

Autopsy ​

Features:

  • Timeline analysis
  • File recovery
  • Keyword search
  • Hash filtering
  • Registry analysis

Volatility ​

bash
# Memory analysis:
volatility -f memory.dump imageinfo
volatility -f memory.dump --profile=Win10x64 pslist
volatility -f memory.dump --profile=Win10x64 filescan

🎯 CTF Specific ​

PwnTools (Python) ​

python
from pwn import *

# Connect to service
conn = remote('challenge.com', 1337)

# Send/receive data
conn.send('payload')
response = conn.recv()

# Pattern creation
pattern = cyclic(100)

RsaCtfTool ​

bash
# Basic usage:
python3 RsaCtfTool.py --publickey key.pub --private
python3 RsaCtfTool.py --attack fermat --n [modulus]

💻 Development Tools ​

OpenSSL CLI ​

bash
# Generate certificates:
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365

# View certificate info:
openssl x509 -in cert.pem -text

# Generate random bytes:
openssl rand -hex 32

Key Generation Tools ​

bash
# SSH Key Generation:
ssh-keygen -t ed25519 -C "your_email@example.com"

# GPG Key Generation:
gpg --full-generate-key

📱 Mobile Security ​

Mobile Security Framework (MobSF) ​

Features:

  • Static analysis
  • Dynamic analysis
  • Web API testing
  • Malware analysis

Frida ​

javascript
// Basic Frida script
Java.perform(() => {
    const MainActivity = Java.use('com.example.app.MainActivity');
    MainActivity.checkPassword.implementation = function(password) {
        console.log('Password check bypassed');
        return true;
    };
});

🎓 Learning Resources ​

Practice Platforms ​

  • HackTheBox
  • TryHackMe
  • OverTheWire
  • PicoCTF
  • CryptoHack

Online Tools ​

  • CrackStation (Rainbow tables)
  • dCode (Cipher tools)
  • HashKiller
  • JWT.io
  • SSL Labs

🚀 Quick Start Guide ​

  1. For Beginners:

    • Start with CyberChef
    • Learn basic command-line tools
    • Practice with CTF platforms

  2. For Intermediate:

    • Master Wireshark/Burp Suite
    • Learn scripting with PwnTools
    • Experiment with HashCat/John

  3. For Advanced:

    • Develop custom tools
    • Contribute to open source
    • Automate your workflow

🔗 Tool Combinations ​

Common Workflows ​

mermaid
graph LR
    A[Wireshark] --> B[CyberChef]
    B --> C[HashCat]
    C --> D[Custom Scripts]

Automated Analysis Pipeline ​

python
#!/usr/bin/env python3
import subprocess
import sys

def analyze_file(filename):
    # Run multiple tools
    strings = subprocess.check_output(['strings', filename])
    hexdump = subprocess.check_output(['hexdump', '-C', filename])
    
    # Process results
    # Your analysis logic here

🛡️ Safety and Ethics ​

Best Practices ​

  1. Always work in isolated environments
  2. Keep tools and systems updated
  3. Handle sensitive data appropriately
  4. Document your processes
  5. Follow responsible disclosure
  • Only test systems you own/have permission to test
  • Respect privacy and data protection laws
  • Keep evidence of authorization
  • Document all activities

🔄 Regular Updates ​

Stay current with:

  • Tool updates and new releases
  • Security advisories
  • Community developments
  • New attack techniques
  • Defense mechanisms

🤝 Community Resources ​

Forums and Communities ​

  • Reddit (r/netsec, r/crypto)
  • Stack Exchange
  • GitHub Discussions
  • Discord servers
  • Local meetups

Contributing ​

  • Report bugs
  • Submit patches
  • Share tools
  • Write documentation
  • Help others learn

Remember: Tools are only as good as the person using them. Keep learning, stay curious, and practice responsibly! 🚀

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