M-Security #

A native Rust security SDK for Flutter, providing high-performance cryptographic services, streaming encryption with compression, an encrypted virtual file system (EVFS), and secure memory management. All operations run in Rust through Flutter Rust Bridge. No Dart-level crypto, no platform channels.

Built and maintained by the Dev Department of MicroClub, the computer science club at USTHB (University of Science and Technology Houari Boumediene, Algiers).

Features #

Security by design:

• All key material lives in Rust behind opaque handles; raw keys never cross FFI
• Automatic memory zeroization on drop (ZeroizeOnDrop)
• Nonces generated internally via OS-level CSPRNG (OsRng)
• AEAD tag verification prevents silent decryption of tampered data
• panic = "abort" in release profile, preventing undefined behavior from panics crossing FFI
• clippy::unwrap_used = "deny", ensuring all operations return Result<T, CryptoError>

Installation #

Add to your pubspec.yaml:

dependencies:
  m_security: ^0.3.0

Then run:

flutter pub get

Prerequisites #

M-Security compiles Rust code during the Flutter build. You need:

• Rust toolchain (stable):

  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
  

• Platform-specific tools:

  Platform	Requirements
  Android	Android NDK (r27c recommended)
  iOS / macOS	Xcode with command line tools
  Linux	clang, cmake, ninja-build, pkg-config, libgtk-3-dev
  Windows	Visual Studio Build Tools + LLVM

Rust compilation is handled automatically by Cargokit during flutter build / flutter run.

Getting Started #

Initialize the Rust library once at app startup:

import 'package:m_security/m_security.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await RustLib.init();
  runApp(const MyApp());
}

Usage #

All examples below use a single import:

import 'package:m_security/m_security.dart';

AES-256-GCM Encryption #

final aes = AesGcmService();
await aes.initWithRandomKey();

// Encrypt and decrypt raw bytes
final encrypted = await aes.encrypt(plaintext);
final decrypted = await aes.decrypt(encrypted);

// Convenience: encrypt and decrypt UTF-8 strings
final ciphertext = await aes.encryptString('sensitive data');
final original = await aes.decryptString(ciphertext);

ChaCha20-Poly1305 Encryption #

final chacha = Chacha20Service();
await chacha.initWithRandomKey();

// Basic encrypt and decrypt
final encrypted = await chacha.encryptString('sensitive data');
final original = await chacha.decryptString(encrypted);

// With Associated Authenticated Data (AAD)
final ct = await chacha.encryptString('payload', aad: 'metadata');
final pt = await chacha.decryptString(ct, aad: 'metadata');

Both ciphers output nonce || ciphertext || tag. Nonces (12 bytes) are auto-generated and authentication tags (16 bytes) are appended automatically.

Argon2id Password Hashing #

// Hash a password (returns PHC-format string)
final hash = await argon2IdHash(password: 'hunter2');

// Verify a password against a hash
await argon2IdVerify(phcHash: hash, password: 'hunter2');

// Explicit preset selection
final hash = await argon2IdHash(
  password: 'hunter2',
  preset: Argon2Preset.desktop,  // 256 MiB, t=4, p=8
);

The default preset is selected at compile time: Argon2Preset.mobile (64 MiB, t=3, p=4) unless built with -DIS_DESKTOP=true.

HKDF-SHA256 Key Derivation #

// Derive a key from input key material
final key = MHKDF.derive(
  ikm: masterKeyBytes,
  salt: saltBytes,          // optional
  info: Uint8List.fromList('encryption-key'.codeUnits),
  outputLen: 32,
);

// Domain separation: same master key, different derived keys
final encKey = MHKDF.derive(ikm: master, info: utf8.encode('enc'), outputLen: 32);
final macKey = MHKDF.derive(ikm: master, info: utf8.encode('mac'), outputLen: 32);

// Two-phase: extract PRK, then expand
final prk = MHKDF.extract(ikm: masterKeyBytes, salt: saltBytes);
final derived = await MHKDF.expand(prk: prk, info: infoBytes, outputLen: 32);

Output length must be between 1 and 8160 bytes (RFC 5869 limit for SHA-256: 255 * 32).

Streaming Encryption #

import 'package:m_security/src/rust/api/streaming.dart';

// Encrypt a file in chunks with progress
final encrypted = await streamEncrypt(
  plaintext: largeData,
  algorithm: StreamAlgorithm.aes256Gcm,
  compression: CompressionAlgorithm.zstd,
  compressionLevel: 3,
  onProgress: (progress) => print('${(progress * 100).toInt()}%'),
);

// Decrypt
final decrypted = await streamDecrypt(
  ciphertext: encrypted,
  algorithm: StreamAlgorithm.aes256Gcm,
  compression: CompressionAlgorithm.zstd,
);

Encrypted Virtual File System (EVFS) #

import 'package:m_security/m_security.dart';

// Create a vault
final vault = VaultService();
await vault.create(path: '/path/to/my.vault', sizeBytes: 10 * 1024 * 1024);

// Write a segment (with optional compression)
await vault.writeSegment(
  name: 'secret.txt',
  data: utf8.encode('confidential'),
  compression: CompressionAlgorithm.zstd,
);

// Read it back
final data = await vault.readSegment(name: 'secret.txt');

// List segments, delete, close
final segments = await vault.listSegments();
await vault.deleteSegment(name: 'secret.txt');
await vault.close();

BLAKE3 & SHA-3-256 Hashing #

For one-shot and streaming hashing, use the lower-level FFI API directly:

import 'package:m_security/src/rust/api/hashing.dart';

// One-shot hashing (32-byte output)
final blake3Digest = await blake3Hash(data: inputBytes);
final sha3Digest = await sha3Hash(data: inputBytes);

// Streaming: process data in chunks
final hasher = createBlake3();  // or createSha3()
await hasherUpdate(handle: hasher, data: chunk1);
await hasherUpdate(handle: hasher, data: chunk2);
final digest = await hasherFinalize(handle: hasher);

// Reset and reuse
await hasherReset(handle: hasher);

Architecture #

Key design decisions:

• Opaque handles. CipherHandle and HasherHandle are #[frb(opaque)]. Dart holds a pointer, never raw key bytes.
• Trait objects. Box<dyn Encryption> and Box<dyn Hasher> with Send + Sync + 'static enable runtime algorithm selection.
• SecretBuffer. All key material is wrapped in SecretBuffer which derives ZeroizeOnDrop. Memory is zeroed when handles are dropped.
• No panics across FFI. panic = "abort" in release profile. All FFI functions return Result<T, CryptoError>.
• Format headers. Encrypted data includes a MSEC magic header with version and algorithm identifiers for forward compatibility.

Rust API Reference #

Encryption (CipherHandle) #

create_aes256_gcm(key: Vec<u8>)              -> Result<CipherHandle>
create_chacha20_poly1305(key: Vec<u8>)       -> Result<CipherHandle>
encrypt(cipher, plaintext, aad)              -> Result<Vec<u8>>
decrypt(cipher, ciphertext, aad)             -> Result<Vec<u8>>
generate_aes256_gcm_key()                    -> Result<Vec<u8>>
generate_chacha20_poly1305_key()             -> Result<Vec<u8>>
encryption_algorithm_id(cipher)              -> String

Hashing (HasherHandle) #

blake3_hash(data)           -> Vec<u8>          (one-shot, 32 bytes)
sha3_hash(data)             -> Vec<u8>          (one-shot, 32 bytes)
create_blake3()             -> HasherHandle      (streaming)
create_sha3()               -> HasherHandle      (streaming)
hasher_update(handle, data) -> Result<()>
hasher_reset(handle)        -> Result<()>
hasher_finalize(handle)     -> Result<Vec<u8>>
hasher_algorithm_id(handle) -> Result<String>

Password Hashing (Argon2id) #

argon2id_hash(password, preset)                     -> Result<String>  (PHC)
argon2id_hash_with_salt(password, salt, preset)     -> Result<String>  (PHC)
argon2id_verify(phc_hash, password)                 -> Result<()>

Presets: Mobile (64 MiB, t=3, p=4) | Desktop (256 MiB, t=4, p=8)

Key Derivation (HKDF-SHA256) #

hkdf_derive(ikm, salt?, info, output_len)   -> Result<Vec<u8>>   (one-shot)
hkdf_extract(ikm, salt?)                    -> Result<Vec<u8>>   (PRK)
hkdf_expand(prk, info, output_len)          -> Result<Vec<u8>>

Platform Support #

Testing #

Rust unit tests (79 tests including NIST/RFC test vectors):

cd rust && cargo test

Dart integration tests (63 tests across all features, requires a running device/simulator):

cd example
flutter test integration_test/

Tech Stack #

Rust crates: aes-gcm 0.10, chacha20poly1305 0.10, blake3 1.8, sha3 0.10, argon2 0.5, hkdf 0.12, zstd 0.13, brotli 7.0, zeroize 1.8

Roadmap #

Contributing #

See CONTRIBUTING.md for development setup, coding standards, and PR workflow.

License #

MIT. See LICENSE for details.

Copyright (c) 2025 MicroClub-USTHB