Module xwing

Available on crate feature dep_orion only.

X-Wing hybrid KEM as specified in draft-connolly-cfrg-xwing-kem-06.

Parameters:

• ek: The public encapsulation key, for which a shared secret and ciphertext is generated.
• dk: The secret decapsulation key, for which a ciphertext is used to derive a shared secret.
• c: The public ciphertext, sent to the decapsulating party.
• eseed: Explicit randomness used for encapsulation.

Errors:

An error will be returned if:

• eseed is not 64 bytes.
• getrandom::fill() fails during encapsulation.

Panics:

A panic will occur if:

• getrandom::fill() fails during KeyPair::generate().

Security:

• It is critical that both the seed and explicit randomness eseed, used for key generation and encapsulation are generated using a strong CSPRNG.
• Users should always prefer encapsulation without specifying explicit randomness, if possible. encap_deterministic() exists mainly for no_std usage.

Example:

use orion::hazardous::kem::xwing::*;

let keypair = KeyPair::generate()?;

let (sender_shared_secret, sender_ciphertext) = XWing::encap(keypair.public())?;
let recipient_shared_secret = XWing::decap(keypair.private(), &sender_ciphertext)?;

assert_eq!(sender_shared_secret, recipient_shared_secret);

Structs

Ciphertext

A type to represent the KEM Ciphertext that X-Wing returns.

DecapsulationKey

A type to represent the DecapsulationKey that X-Wing produces. This type’s foremost responsibility is to cache key-expansions, to be re-used across multiple decapsulations with a single secret.

EncapsulationKey

A type to represent the public EncapsulationKey that X-Wing uses.

KeyPair

A keypair of X-Wing keys.

Seed

A type to represent the private Seed that X-Wing uses.

SharedSecret

A type to represent the private SharedSecret that X-Wing returns.

XWing

X-Wing hybrid KEM.

Constants

CIPHERTEXT_SIZE

Size of public Ciphertext.

PRIVATE_KEY_SIZE

Size of private DecapsulationKey.

PUBLIC_KEY_SIZE

Size of public EncapsulationKey.

SHARED_SECRET_SIZE

Size of private SharedSecret.