A Professional Dual-Table Unicode Substitution Cipher

Developed by Axxo | The NULL

A deterministic two-table Unicode substitution cipher built with extensive validation, integrity verification, automated testing, and reversible encryption.

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Overview

• C1ZX is a Unicode-based substitution cipher that encrypts printable ASCII characters using two independent substitution tables.

• Unlike a traditional monoalphabetic substitution cipher, C1ZX alternates between two completely separate lookup tables depending on the character index.

• Even indexed characters use one table.

• Odd indexed characters use another.

• This significantly reduces simple repetition patterns while maintaining deterministic and fully reversible encryption.

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Features

• 🔒 Dual-table substitution cipher
• 🌍 Unicode symbol encryption
• 🔄 Fully reversible encryption
• 🧪 Built-in automated self-testing
• ✅ Extensive validation before startup
• ⚡ O(n) encryption and decryption
• 📦 Single-file implementation
• 🖥 Terminal Unicode compatibility detection
• 🧩 Immutable cipher configuration
• 📚 Well documented source code

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Architecture

Program
│
├── Constants
├── Unicode Symbol Pool
├── Validation System
├── Table Generator
├── Reverse Table Builder
├── Cipher Engine
├── Self Tests
├── Terminal Compatibility
├── User Interface
└── Main Entry Point

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Cryptographic Design

• C1ZX uses two completely independent substitution tables.

Index 0 → TABLE_01
Index 1 → TABLE_02
Index 2 → TABLE_01
Index 3 → TABLE_02
...

Example

Plaintext

HELLO

↓

H → TABLE_01
E → TABLE_02
L → TABLE_01
L → TABLE_02
O → TABLE_01

↓

Unicode Ciphertext

• Each table owns its own exclusive Unicode symbol pool.

• No encrypted symbol exists in both tables.

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Initialization Sequence

• Before encryption is possible the application performs:

Validate Unicode Symbols
        │
        ▼
Generate TABLE_01
        │
        ▼
Generate TABLE_02
        │
        ▼
Validate Tables
        │
        ▼
Build Reverse Tables
        │
        ▼
Validate Reverse Tables
        │
        ▼
Run Self Tests
        │
        ▼
Ready

• If any validation fails, the application exits immediately.

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Self Tests

• Every launch automatically performs comprehensive testing.

• Included tests:

  • Supported character round-trip
  • Entire character set verification
  • Empty string handling
  • Random string encryption
  • Long text encryption
  • Unicode passthrough
  • Whitespace preservation
  • Control character passthrough
  • Reverse table integrity
  • Alternating parity verification
  • Symbol overlap detection

Only after every test passes does the program become available.

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📂 Project Structure

.
├── main.py
├── LICENSE
└── README.md

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Installation

Clone the repository

git clone https://github.com/axxodeveloper/C1ZX.git

Enter the project

cd C1ZX

Run the application

python main.py

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Requirements

• Python 3.9+

• UTF-8 compatible terminal

• No external dependencies are required.

• Only Python's standard library is used.

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Main Menu

[1] Encrypt Text

[2] Decrypt Text

[3] About

[0] Exit

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Encryption Workflow

Plaintext

↓

Character Position

↓

Even?
│
├── Yes → TABLE_01
│
└── No → TABLE_02

↓

Unicode Ciphertext

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Decryption Workflow

Ciphertext

↓

Character Position

↓

Even?
│
├── Yes → REV_TABLE_01
│
└── No → REV_TABLE_02

↓

Recovered Plaintext

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Performance

Operation	Complexity
Encryption	O(n)
Decryption	O(n)
Table Lookup	O(1)
Initialization	O(k)

• Where n is the text length.

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Validation System

Before startup C1ZX verifies:

• Unique Unicode symbols
• No duplicate mappings
• Complete character coverage
• Exclusive symbol pools
• Reverse lookup correctness
• Table integrity
• Mapping consistency

This prevents corrupted cipher tables.

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Unicode Support

• C1ZX automatically checks terminal compatibility.

• If Unicode support is unavailable, a warning is displayed before continuing.

• The encryption still functions correctly even if the terminal cannot display the encrypted symbols properly.

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Supported Characters

• The cipher currently supports:

  • Uppercase letters
  • Lowercase letters
  • Numbers
  • ASCII punctuation
  • Space character

Unsupported Unicode characters pass through unchanged.

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⚠ Security Notice

• C1ZX is intended as an educational cryptographic project demonstrating deterministic dual-table substitution.

• It is a replacement for modern cryptographic standards such as:

  • AES
  • ChaCha20
  • RSA
  • ECC

• Sensitive or production data should always be protected using cryptographic libraries and industry-standard algorithms.

• For that purposes you can use this tool.

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License

Distributed under the MIT License.

See LICENSE for more information.

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Author

Axxo | The NULL

Version 2.0.1

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Made with ❤️ using Python

C1ZX Cipher Tool