air_link_secure 0.2.1

End-to-end encryption (E2EE) with Diffie-Hellman key exchange for Air Link.

Changelog

0.2.1

• Added dartdoc comments across the public API.
• Added example/ directory with usage demo.
• Various stability improvements and fixes.

0.2.0

• Key exchange: Replaced insecure XOR-fold KDF with HKDF-SHA256. DH remains on RFC 3526 Group 14 (2048-bit MODP).
• Encryption: Replaced insecure XOR cipher with AES-256-GCM (GCMBlockCipher + AESEngine). 12-byte random IV per packet. Tampered data rejected by GCM authentication tag.
• Identity: Added Identity class for ECDSA secp256r1 key pair generation, signing, and verification. Persistent JSON storage.
• Auth handshake: Added AuthHandshake (SIGMA-like 3-message protocol) with mutual ECDSA signatures, DH session key agreement, HKDF key derivation, and TOFU peer trust database.
• Convenience API: connectSecure() / listenSecure() — one-liner for authenticated + encrypted TCP connections.

0.1.0

• Initial development release with basic DH key exchange and XOR cipher.