substitutionciphers 2.0.0

The Griffinere cipher is a custom encryption algorithm in C# designed for reversible, base64-normalized encryption using a repeating key. Inspired by the Vigenère cipher, it adds configurable alphabet support, input validation, and padding-based encryption length enforcement.

Griffinere Cipher 🔐 — Python Edition

The Griffinere cipher is a reversible, Base‑64‑normalised encryption algorithm implemented in pure Python. Inspired by the classic Vigenère cipher, it adds:

• Configurable alphabets (use any character set you like)
• Input validation for safer usage
• Padding‑based length enforcement so encrypted strings meet a minimum length

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📦 Installation

pip install substitutionciphers

In your code:

from substitutionciphers import Griffinere

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✨ Features

• 🔐 Encrypts & decrypts alphanumeric or custom‑alphabet strings
• 🧩 Define your own alphabet (emoji? Cyrillic? go ahead!)
• 📏 Optional minimum‑length padding for fixed‑width ciphertext
• ✅ Strong validation of both alphabet and key integrity
• 🧪 Unit‑tested with pytest

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🧰 Usage

1 Create a cipher

1.1 Default alphabet

key = "YourSecureKey"
cipher = Griffinere(key)

The built‑in alphabet is:

A‑Z  a‑z  0‑9

1.2 Custom alphabet

custom_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ12345"
key = "YOURKEY"
cipher = Griffinere(key, custom_alphabet)

Alphabet rules

1. Must not contain . (dot)
2. All characters must be unique
3. Every character in the key must appear in the alphabet

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2 Encrypt & decrypt

2.1 Encrypt a string

plain_text = "Hello World 123"
encrypted = cipher.encrypt_string(plain_text)
# e.g. 'LUKsbK8 OK9ybKJ FC3z'

2.2 Encrypt with a minimum length

encrypted = cipher.encrypt_string(plain_text, minimum_response_length=24)
# e.g. 'cm9JbAxsIJg.LUKsbK8 OK9ybKJ FC3z.Fw'

3.1 Decrypt

decrypted = cipher.decrypt_string(encrypted)
assert decrypted == plain_text

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⚠️ Exceptions & validation

Condition	Exception
Alphabet contains .	ValueError
Duplicate characters in alphabet	ValueError
Alphabet is fewer than 3 characters long	ValueError
Key is fewer than 3 characters long	ValueError
Key contains characters not present in alphabet	ValueError
minimum_response_length < 1	ValueError

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📄 License

MIT License © 2025 Riley Griffin