XWingFfiAlgo class final

X-Wing hybrid post-quantum/traditional KEM (IANA HPKE KEM id 0x647A) backed by OpenSSL 3 via Dart FFI.

See XWingPureDartAlgo for which document to cite and why.

X-Wing has no native OpenSSL primitive, so this composes MlKem768FfiAlgo (ML-KEM-768) and X25519FfiAlgo (X25519). The seed expansion (SHAKE-256), the shared-secret combiner (SHA3-256) and the byte layouts are the package-internal XWingCore, shared with XWingPureDartAlgo, so public keys, ciphertexts and shared secrets are fully interoperable between the FFI and pure-Dart backends. This backend is still checked against the published 0x647A vectors in its own right — the working group's JSON is the independent oracle, and interop tests alone would pass with both backends wrong in the same way.

Unlike XWingPureDartAlgo, there is no derandomized encapsulation: OpenSSL's ML-KEM encapsulation does not accept external randomness, so draft test vectors are verified against the pure-Dart backend instead.

Prefer AtPqc.xWing, which auto-resolves to this backend when libcrypto supports ML-KEM-768 and falls back to pure-Dart otherwise. Construct via XWingFfiAlgo.fromLib only to pin a specific DynamicLibrary (e.g. loaded via tryLoadLibCrypto).

Implemented types

• AtKemAlgorithm

Mixed-in types

• KemSeedMixin

Constructors

XWingFfiAlgo.fromLib(DynamicLibrary lib)

Properties

hashCode → int

The hash code for this object.

no setter, inherited

kemSeedDescription → String

How a wrong-length diagnostic names this backend's seed, e.g. an X-Wing seed or an ML-KEM-768 seed (d || z).

no setter, override

kemSeedLength → int

This backend's seed length in bytes. Feeds newSeed and keyPairFromSeed; not part of the caller-facing contract.

no setter, override

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

decapsulate(Uint8List secretKey, Uint8List ciphertext) → Future<Uint8List>

Recover the shared secret from ciphertext using secretKey.

override

encapsulate(Uint8List publicKey) → Future<({Uint8List ciphertext, Uint8List sharedSecret})>

Encapsulate a fresh shared secret against publicKey.

override

generateKeyPair([Uint8List? seed]) → Future<({Uint8List publicKey, Uint8List secretKey})>

Generate an X-Wing key pair.

override

keyPairFromSeed(Uint8List seed) → FutureOr<({Uint8List publicKey, Uint8List secretKey})>

Deterministically regenerate the key pair that seed produces.

inherited

keyPairFromValidatedSeed(Uint8List seed) → Future<({Uint8List publicKey, Uint8List secretKey})>

Unlike MlKem768FfiAlgo, this backend's secret key is the seed itself rather than an OpenSSL handle, so a key recovered through keyPairFromSeed does survive a restart.

override

newSeed() → Uint8List

A fresh seed drawn from a secure random source, of whatever length this backend's keyPairFromSeed takes.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Constants

ciphertextLength → const int

publicKeyLength → const int

seedLength → const int

sharedSecretLength → const int