libsodium

Description:

libsodium

libsodium-dart #
Fix for allowing https://github.com/firstfloorsoftware/flutter_sodium to run in pure-dart non-flutter applications.

Getting Started #
In your dart project add the dependency:
dependencies:
...
libsodium: ^0.2.0
flutter_sodium: ^0.2.0
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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:libsodium/libsodium.dart';

// initialize sodium
Sodium.init();
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Usage example #
// Password hashing (using Argon)
final password = 'my password';
final str = PasswordHash.hashStringStorage(password);

print(str);

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

assert(valid);
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This project includes an extensive example app with runnable code samples. Be sure to check it out!
API coverage #
The libsodium 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);

print(str);
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