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🔐 Mini-RSA

A minimal RSA implementation in Rust for generating keys, encrypting files, and decrypting them using command-line interface. Ideal for educational purposes, learning cryptographic concepts, or lightweight encryption tasks.

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🚀 Features

• Generate RSA key pairs using random two-digit primes
• Save and load public/private keys in readable format
• Encrypt and decrypt binary files using RSA
• Modular CLI interface with clap
• Educational and compact implementation

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🛠️ Installation

1. Clone the repository:

git clone https://github.com/martian58/mini_rsa.git
cd mini-rsa

2. Build the project:

cargo build --release

3. Run the CLI:

./target/release/mini_rsa --help

Or use the prcompiled binaries

mini_rsa-win_v1.0.exe
mini_rsa_v1.0-x86_64-linux 

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📦 Usage

🔑 Generate Keys

./mini_rsa generate --name mykey

Generates:

• mykey.pub: Public key
• mykey: Private key

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🔒 Encrypt a File

./mini_rsa encrypt --input secret.txt --output secret.enc --key mykey.pub

secret.txt → secret.enc

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🔓 Decrypt a File

./mini_rsa decrypt --input secret.enc --output revealed.txt --key mykey

secret.enc → revealed.txt

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🧠 How It Works

• Picks two random two-digit prime numbers.
• Calculates RSA parameters: n, phi, e, and private d.
• Uses modular exponentiation for both encryption and decryption.
• Keys are saved in a simple custom format for easy inspection.

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🔍 Example

$ ./mini_rsa generate --name demo
Keys generated: demo.pub (public), demo (private)

$ ./mini_rsa encrypt -i hello.txt -o hello.enc -k demo.pub
File encrypted: hello.enc

$ ./mini_rsa decrypt -i hello.enc -o hello_out.txt -k demo
File decrypted: hello_out.txt

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📁 Key File Format

Example demo.pub:

-----BEGIN RSA PUBLIC KEY-----
65537 3233
-----END RSA PUBLIC KEY-----

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📚 Dependencies

• clap — Command-line argument parsing
• rand — Random number generation

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⚠️ Disclaimer

This implementation is for educational purposes only and not secure for real-world cryptographic use. It uses small key sizes and lacks padding schemes.

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