crypto-12 0.1.0

Educational cryptography and network security concepts in Python

crypto-12

A pure-Python educational package covering 21 cryptography and network security concepts.
No external dependencies. Works with Python 3.8+.

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📦 Package Structure

crypto-12/
│
├── crypto_12/
│   ├── __init__.py
│   ├── caesar_cipher.py
│   ├── monoalphabetic_cipher.py
│   ├── vigenere_cipher.py
│   ├── playfair_cipher.py
│   ├── hill_cipher.py
│   ├── rail_fence_cipher.py
│   ├── row_column_transposition.py
│   ├── rsa_demo.py
│   ├── diffie_hellman_demo.py
│   ├── sha1_hash.py
│   ├── md5_hash.py
│   ├── gcd_euclidean.py
│   ├── extended_euclidean.py
│   ├── multiplicative_inverse.py
│   ├── affine_cipher.py
│   ├── columnar_transposition.py
│   ├── simple_permutation.py
│   ├── otp_cipher.py
│   ├── frequency_analysis.py
│   ├── sql_injection_demo.py
│   └── nmap_scan_demo.py
│
├── pyproject.toml
└── README.md

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🚀 Installation

Option 1 — Install directly (editable/development mode)

pip install .

Option 2 — Build a distributable wheel, then install

# Install build tool
pip install build

# Build the package
python -m build

# Install the built wheel
pip install dist/crypto_12-0.1.0-py3-none-any.whl

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🔧 Usage

After installing, you can import and use any module:

from crypto_12 import caesar_cipher

caesar_cipher.run()

Or call individual functions:

from crypto_12.caesar_cipher import encrypt, decrypt

encrypted = encrypt("HELLO WORLD", 3)
decrypted = decrypt(encrypted, 3)
print(encrypted)  # KHOOR ZRUOG
print(decrypted)  # HELLO WORLD

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📚 Module Reference

Substitution Ciphers

Module	Description
caesar_cipher	Shift cipher — each letter shifted by a fixed amount
monoalphabetic_cipher	Arbitrary fixed substitution using a 26-letter key alphabet
vigenere_cipher	Polyalphabetic cipher using a repeating keyword
playfair_cipher	Digraph cipher using a 5×5 key matrix
hill_cipher	Linear algebra cipher using a 2×2 invertible matrix (mod 26)
affine_cipher	C = (a*P + b) mod 26 with modular inverse for decryption

Transposition Ciphers

Module	Description
rail_fence_cipher	Zig-zag pattern writing across N rails
row_column_transposition	Write in rows, read columns sorted by key
columnar_transposition	Column reordering based on alphabetical key ranking
simple_permutation	Rearranges character positions within fixed-length blocks

Public Key / Key Exchange

Module	Description
rsa_demo	Simplified RSA: key generation, encrypt/decrypt with small primes
diffie_hellman_demo	DH key exchange: shared secret agreement over public channel

Hashing

Module	Description
sha1_hash	Pure-Python SHA-1 implementation (160-bit hash)
md5_hash	Pure-Python MD5 implementation (128-bit hash)

Number Theory / Math Utilities

Module	Description
gcd_euclidean	GCD with step-by-step Euclidean trace
extended_euclidean	Extended GCD returning Bezout coefficients
multiplicative_inverse	Modular inverse: a * x ≡ 1 (mod m)

Cryptanalysis

Module	Description
frequency_analysis	Letter frequency counter + Caesar shift guesser
otp_cipher	One-Time Pad simulation using XOR + random key

Security Awareness (Safe Demos)

Module	Description
sql_injection_demo	Explains SQL injection with safe/vulnerable query comparison
nmap_scan_demo	Nmap command reference; prints examples only, no real scanning

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▶️ Running Individual Modules Interactively

Each module has a run() function with interactive prompts:

python -c "from crypto_12 import vigenere_cipher; vigenere_cipher.run()"
python -c "from crypto_12 import rsa_demo; rsa_demo.run()"
python -c "from crypto_12 import frequency_analysis; frequency_analysis.run()"

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⚠️ Disclaimer

• The SHA-1 and MD5 implementations are educational and should not be used for security-critical applications.
• The SQL injection demo performs no real database queries.
• The Nmap demo performs no actual network scans.
• RSA and Diffie-Hellman use small numbers for clarity; real implementations require much larger primes.

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📄 License

MIT License — free to use for learning and educational purposes.