vastdisk-crypto

Rust crypto core for VASTDISK. Licensed under AGPLv3 for full transparency and auditability.

What It Provides

• AES-256-GCM chunked encryption/decryption (1 MB chunks, random IV per chunk)
• BLAKE3 hashing
• Ed25519 signature verification (for deletion proofs)
• Optional WASM bindings via wasm-bindgen

Usage

use vastdisk_crypto::{encrypt, decrypt, hash_blake3, verify_deletion_proof, DeletionPayload};

// Encrypt
let result = encrypt(b"secret data");
println!("key: {}", result.key_b64);

// Decrypt
let plaintext = decrypt(&result.ciphertext, &result.key_b64).unwrap();

// Hash
let hash = hash_blake3(b"some data");

// Verify deletion proof
let valid = verify_deletion_proof(&payload, &signature_b64, &public_key_b64);

WASM

Build with --features wasm and use wasm-pack build:

wasm-pack build --features wasm --target web

Wire Format

V2 ciphertexts start with a fixed header, then chunk records:

• Header: [4-byte "VAST"][1-byte version=2][3 reserved bytes][16-byte file nonce]
• Each encrypted chunk: [4-byte BE length][12-byte IV][AES-256-GCM ciphertext+tag]

Chunks are authenticated with AES-GCM additional authenticated data (AAD) that binds the header and chunk index.

Legacy v1 ciphertexts (no header / no AAD binding) are rejected by default.

License

AGPLv3 - see LICENSE. Crypto code is open for audit.