dartage

dartage (pronounced “dart-age”) is a pure-Dart implementation of the age v1 file format with X25519 recipients.

Status: 0.x. The API is in production use but can still change before 1.0. Dotweave is its first consumer.

Scope

Supported: X25519 recipients, the binary format, ASCII armor, age1… / AGE-SECRET-KEY-1… key parsing and generation, and the STREAM payload construction with its 64 KiB chunking.

Not supported: scrypt (passphrase) recipients. A file containing an scrypt stanza is rejected with AgeExceptionCode.passphraseUnsupported rather than silently mishandled.

Usage

import 'dart:convert';
import 'dart:typed_data';

import 'package:dartage/dartage.dart';

Future<void> main() async {
  final identity = generateIdentity();
  final recipient = await identityToRecipient(identity);

  final encrypter = AgeEncrypter()..addRecipient(recipient);
  final ciphertext = await encrypter.encrypt(
    Uint8List.fromList(utf8.encode('secret')),
  );

  final decrypter = AgeDecrypter()..addIdentity(identity);
  print(utf8.decode(await decrypter.decrypt(ciphertext)));
}

Use armorEncode / armorDecode for the PEM-style ASCII form.

Correctness

The implementation is checked against a 30-vector fixture corpus covering armor edge cases, header MAC tampering, truncated and non-canonical STREAM payloads, low-order and non-canonical X25519 shares, grease stanzas, and multi-recipient files. A separate interop suite encrypts and decrypts in both directions against the reference age-encryption npm package, so wire compatibility is verified rather than assumed:

cd test/interop && pnpm install
dart test -t interop

The offline run is dart test -x interop.