Experimental ARX-based file encryption tool written in Rust. Custom cipher (Bastion-256). Open design. Cryptanalysis welcome.

Bastion-F is an experimental ARX-based stream cipher designed for educational and research purposes.

This project actively invites cryptanalysis.

We welcome:

• distinguishers from random
• reduced-round attacks
• key recovery attempts
• analysis of the key schedule and diffusion
• related-key or nonce-misuse analysis

This is NOT production cryptography.

This project is written in Rust and requires a recent stable toolchain.

Note that you can download compiled Bastion here: Download Bastion.exe v0.0.4

• Rust 1.70+ (stable)
• Cargo

git clone https://github.com/Bastion-F/bastion-f.git
cd bastion-f
cargo build --release

The resulting binary will be located at:

target/release/bastion-f

Bastion-F is a local file encryption tool.

bastion-f --encrypt --path secret.txt

This produces:

secret.txt.bastion

bastion-f --decrypt --path secret.txt.bastion

This restores:

secret.txt.dec

bastion-f --encrypt --path secret.txt --shred

⚠️ Shredding is best-effort only and may not be reliable on SSDs or log-structured file systems.

$ bastion-f --encrypt --path notes.md
🛡️  Bastion-F v0.0.4 | Terminal
🔑 Enter a master-key: ********
⠁ Reading & Compressing... [00:00:00]
🗜️  Compression finished.
🔑 Keys derived safely.
⚙️  Encryption complete. [########################################] 100%
✍️  Digital signature added.
✅ DONE: notes.md.bastion

$ bastion-f --decrypt --path notes.md.bastion
🛡️  Bastion-F v0.0.4 | Terminal
🔑 Enter a master-key: ********
⠁ Reconstructing keys... [00:00:00]
🔑 Keys reconstructed.
🛡️  Signature valid.
⚙️  Decryption complete. [########################################] 100%
🔓 File restored.

• Bastion-F is not a replacement for AES or ChaCha20
• The cipher has not undergone extensive public cryptanalysis
• Use for experimentation, learning, and research only

If you find a weakness, open an issue or contact the author.

Breaking this cipher is considered a contribution.