Awesome Open Source
Awesome Open Source


With flutter_sodium you get access to the modern, easy-to-use libsodium crypto library in your Flutter apps. One set of crypto APIs supporting both Android and iOS.


Getting Started

In your flutter project add the dependency:

  flutter_sodium: ^0.2.0

Import the plugin and initialize it. Sodium.init() initializes the plugin and should be called before any other function provided by flutter_sodium.

import 'package:flutter_sodium/flutter_sodium.dart';

// initialize sodium

Usage example

// Password hashing (using Argon)
final password = 'my password';
final str = PasswordHash.hashStringStorage(password);


// verify hash str
final valid = PasswordHash.verifyStorage(str, password);


This project includes an extensive example app with runnable code samples. Be sure to check it out!

API coverage

The flutter_sodium plugin implements the following libsodium APIs:

  • crypto_aead
  • crypto_auth
  • crypto_box
  • crypto_generichash
  • crypto_hash
  • crypto_kdf
  • crypto_kx
  • crypto_onetimeauth
  • crypto_pwhash
  • crypto_scalarmult
  • crypto_secretbox
  • crypto_secretstream
  • crypto_shorthash
  • crypto_sign
  • crypto_stream
  • randombytes
  • sodium_version

API coverage is not 100% complete, track the progress in issue #61

Dart APIs

The plugin includes a core API that maps native libsodium functions 1:1 to Dart equivalents. The core API is available in the class Sodium. Dart naming conventions are used for core API function names. A native libsodium function such as crypto_pwhash_str, is available in flutter as Sodium.cryptoPwhashStr.

Also included in flutter_sodium is a high-level, opinionated API providing access to libsodium in a Dart friendly manner. The various functions are available in separate Dart classes. Password hashing for example is available in the PasswordHash class. The high-level API depends on the core API to get things done.

Migrating to fluttter_sodium FFI

The FFI implementation of flutter_sodium is backwards incompatible with the previous platform channel implementation. The list of changes:

  • the entire FFI API is now synchronous, while the previous implementation was entirely asynchronous
  • all hardcoded libsodium constants are now available as properties on the Sodium class.
  • in the platform channel versions the Android and iOS implementations were not in sync. Some functions were available only in iOS, others only in Android. With the FFI implementation, there is a single API covering both platforms.

Background threads

Since the entire FFI API is synchronous, you'll need to do some extra work to execute long running crypto function on a background thread. Luckily this is very easy with Flutter's compute function.

The following code snippet demonstrates running a password hash on the background thread.

final pw = 'hello world';
final str = await compute(PasswordHash.hashStringStorageModerate, pw);


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