Struct DecapsulationKeyRejectNonContrib 

pub struct DecapsulationKeyRejectNonContrib(pub(crate) DecapsulationKey);

X-Wing decapsulation key or private key.

This decapsulation key rejects “non-contributory behaviour” in the X25519 component of X-Wing. To accept instead, use DecapsulationKey.

Backstory

RFC 7748 defines the X25519 function, and specifies that when used for ECDH (as it is inside X-Wing), the implementation MAY abort if the all-zero value is produced as a shared secret. X-Wing, as initially specified, used the X25519 function without making any mention of this MAY, meaning that implementations inherited whatever behaviour their underlying X25519 ECDH implementation provided.

This crate initially did not check for non-contributory behaviour, which meant it was incompatible with other implementations that did (in that it would accept ciphertexts that other implementations reject).

CFRG have decided that they will pick a single behaviour for the IETF X-Wing standard. Until the corresponding RFC is published, this crate supports both behaviours: constructing a DecapsulationKey accepts non-contributory behaviour for backwards-compatibility with existing usages, and this struct can be used to instead reject non-contributory behaviour. Once the RFC is published, DecapsulationKey will be altered to match it.

Tuple Fields

0: DecapsulationKey

Trait Implementations

impl Clone for DecapsulationKeyRejectNonContrib

fn clone(&self) -> DecapsulationKeyRejectNonContrib

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DecapsulationKeyRejectNonContrib

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Decapsulator for DecapsulationKeyRejectNonContrib

type Kem = XWingKem

KEM algorithm this decapsulator is for.

fn encapsulation_key(&self) -> &EncapsulationKey

Encapsulation key which can encrypt ciphertexts this decapsulator can decrypt.

impl From<[u8; 32]> for DecapsulationKeyRejectNonContrib

fn from(sk: [u8; 32]) -> Self

Converts to this type from the input type.

impl Generate for DecapsulationKeyRejectNonContrib

fn try_generate_from_rng<R>(rng: &mut R) -> Result<Self, R::Error>

where R: TryCryptoRng + ?Sized,

Generate random key using the provided TryCryptoRng.

fn generate_from_rng<R>(rng: &mut R) -> Self

where R: CryptoRng + ?Sized,

Generate random key using the provided CryptoRng.

fn try_generate() -> Result<Self, Error>

Randomly generate a value of this type using the system’s ambient cryptographically secure random number generator.

fn generate() -> Self

Randomly generate a value of this type using the system’s ambient cryptographically secure random number generator.

impl KeyExport for DecapsulationKeyRejectNonContrib

fn to_bytes(&self) -> Key<Self>

Serialize this key as a byte array.

impl KeyInit for DecapsulationKeyRejectNonContrib

fn new(key: &Key<Self>) -> Self

Create new value from fixed size key.

fn new_from_slice(key: &[u8]) -> Result<Self, InvalidLength>

Create new value from variable size key.

fn generate_key<R>(rng: &mut R) -> Array<u8, Self::KeySize>

where R: CryptoRng,

👎Deprecated since 0.2.0:

use the Generate trait impl on Key instead

DEPRECATED: generate random key using the provided CryptoRng.

impl KeySizeUser for DecapsulationKeyRejectNonContrib

type KeySize = UInt<UInt<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>, B0>, B0>

Key size in bytes.

fn key_size() -> usize

Return key size in bytes.

impl TryDecapsulate for DecapsulationKeyRejectNonContrib

type Error = DecapsulationError

Decapsulation error

fn try_decapsulate(&self, ct: &Ciphertext) -> Result<SharedKey, Self::Error>

Decapsulates the given Ciphertext a.k.a. “encapsulated key”.